Number 21

Number 21 spell 🔊, write in words: twenty-one . Ordinal number 21th is said 🔊 and write: twenty-first. The meaning of number 21 in Maths: Is Prime? Factorization and dividers. The square root and cube root of 21. The meaning in computer science, numerology, codes and images, writing and naming in other languages, other interesting facts, news.

Useful information about number 21

The decimal (Arabic) number 21 converted to a Roman number is XXI. Roman and decimal number conversions.
The number 21 converted to a Mayan number is mayan number 21
Decimal and Mayan number conversions.

Weight conversion


21 kilograms (kg) = 46.3 pounds (lb)
21 pounds (lb) = 9.5 kilograms (kg)

Length conversion


21 kilometers (km) equals to 13.049 miles (mi).
21 miles (mi) equals to 33.796 kilometers (km).
21 meters (m) equals to 33.796 feet (ft).
21 feet (ft) equals 6.401 meters (m).
21 centimeters (cm) equals to 8.3 inches (in).
21 inches (in) equals to 53.3 centimeters (cm).

Temperature conversion


21° Fahrenheit (°F) equals to -6.1° Celsius (°C)
21° Celsius (°C) equals to 69.8° Fahrenheit (°F)

Power conversion


21 Horsepower (hp) equals to 15.44 kilowatts (kW)
21 kilowatts (kW) equals to 28.56 horsepower (hp)

Codes and images of the number 21

Number 21 morse code: ..--- .----
Sign language for number 21:
Sign language for number 21 Sign language for number 21
Images of the number
Image (1) of the numberImage (2) of the number
Number 21 black image Number 21 red image
There is no copyright for these images. Number 21 infographic.
More images, other sizes, codes and colors ...

Gregorian, Hebrew, Islamic, Persian and Buddhist year (calendar)

Gregorian year 21 is Buddhist year 564.
Buddhist year 21 is Gregorian year 522 a. C.
Gregorian year 21 is Islamic year -620 or -618.
Islamic year 21 is Gregorian year 641 or 642.
Gregorian year 21 is Persian year -602 or -601.
Persian year 21 is Gregorian 642 or 643.
Gregorian year 21 is Hebrew year 3781 or 3782.
Hebrew year 21 is Gregorian year 3739 a. C.
The Buddhist calendar is used in Sri Lanka, Cambodia, Laos, Thailand, and Burma. The Persian calendar is official in Iran and Afghanistan.

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Mathematics of no. 21

Multiplications

Multiplication table of 21


21 multiplied by two equals 42 (21 x 2 = 42).
21 multiplied by three equals 63 (21 x 3 = 63).
21 multiplied by four equals 84 (21 x 4 = 84).
21 multiplied by five equals 105 (21 x 5 = 105).
21 multiplied by six equals 126 (21 x 6 = 126).
21 multiplied by seven equals 147 (21 x 7 = 147).
21 multiplied by eight equals 168 (21 x 8 = 168).
21 multiplied by nine equals 189 (21 x 9 = 189).
show multiplications by 6, 7, 8, 9 ...

Fractions: decimal fraction and common fraction

Fraction table of 21


Half of 21 is 10,5 (21 / 2 = 10,5 = 10 1/2).
One third of 21 is 7 (21 / 3 = 7).
One quarter of 21 is 5,25 (21 / 4 = 5,25 = 5 1/4).
One fifth of 21 is 4,2 (21 / 5 = 4,2 = 4 1/5).
One sixth of 21 is 3,5 (21 / 6 = 3,5 = 3 1/2).
One seventh of 21 is 3 (21 / 7 = 3).
One eighth of 21 is 2,625 (21 / 8 = 2,625 = 2 5/8).
One ninth of 21 is 2,3333 (21 / 9 = 2,3333 = 2 1/3).
show fractions by 6, 7, 8, 9 ...

Calculator

21

Advanced math operations

Is Prime?


The number 21 is not a prime number. The closest prime numbers are 19, 23.
21th prime number in order is 73.

Factorization and dividers


Factorization 3 * 7 = 21
Divisors of number 21 are 1 , 3 , 7 , 21
Total Divisors 4.
Sum of Divisors 32.

Powers


The second power of 212 is 441.
The third power of 213 is 9.261.

Roots


The square root √21 is 4,582576.
The cube root of 321 is 2,758924.

Logarithms


The natural logarithm of No. ln 21 = loge 21 = 3,044522.
The logarithm to base 10 of No. log10 21 = 1,322219.
The Napierian logarithm of No. log1/e 21 = -3,044522.

Trigonometric functions

The cosine of 21 is -0,547729.
The sine of 21 is 0,836656.
The tangent of 21 is -1,527499.

Properties of the number 21

Is a Friedman number: No
Is a Fibonacci number: Yes
Is a Bell number: No
Is a palindromic number: No
Is a pentagonal number: No
Is a perfect number: No

Number 21 in Computer Science

Code typeCode value
Port 21/TCPFTP Protocol (control) - port for FTP commands and flow control
Unix timeUnix time 21 is equal to Thursday Jan. 1, 1970, 12:21 a.m. GMT
IPv4, IPv6Number 21 internet address in dotted format v4 0.0.0.21, v6 ::15
21 Decimal = 10101 Binary
21 Decimal = 210 Ternary
21 Decimal = 25 Octal
21 Decimal = 15 Hexadecimal (0x15 hex)
21 BASE64MjE=
21 MD53c59dc048e8850243be8079a5c74d079
21 SHA1472b07b9fcf2c2451e8781e944bf5f77cd8457c8
21 SHA224112a6cfa3ed398a5248c479ed6a061d397633a3fb4d5b9ecca274695
21 SHA2566f4b6612125fb3a0daecd2799dfd6c9c299424fd920f9b308110a2c1fbd8f443
21 SHA384395809b7b4da42f70785d72cc237e64c7916fa6b2167c15202c09915071639718369426689502bd6a7b60e24cd90d8e8
More SHA codes related to the number 21 ...

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Numerology 21

The meaning of the number 2 (two), numerology 2

Character frequency 2: 1

The number two (2) needs above all to feel and to be. It represents the couple, duality, family, private and social life. He/she really enjoys home life and family gatherings. The number 2 denotes a sociable, hospitable, friendly, caring and affectionate person. It is the sign of empathy, cooperation, adaptability, consideration for others, supersensitivity towards the needs of others. The number 2 (two) is also the symbol of balance, togetherness and receptivity. He/she is a good partner, colleague or companion; he/she also plays a wonderful role as a referee or mediator. Number 2 person is modest, sincere, spiritually influenced and a good diplomat. It represents intuition and vulnerability.
More about the meaning of the number 2 (two), numerology 2 ...

The meaning of the number 1 (one), numerology 1

Character frequency 1: 1

Number one (1) came to develop or balance creativity, independence, originality, self-reliance and confidence in the world. It reflects power, creative strength, quick mind, drive and ambition. It is the sign of individualistic and aggressive nature.
More about the meaning of the number 1 (one), numerology 1 ...

Interesting facts about the number 21

Asteroids

  • (21) Lutetia is asteroid number 21. It was discovered by H. M. S. Goldschmidt from Paris on 11/15/1852.

Aircrafts and flights

  • 07/08/1965 the Canadian Pacific Air Lines plane, flight number 21, Douglas DC-6B crashed in near 100 Mile House, BC, Canada 46 passengers and 6 crew members died.

Areas, mountains and surfaces

  • The total area of Nauru is 8.1 square miles (21 km²)
  • The total area of Hokkaido is 30,394 square miles (78,719 square km). Country Japan (Hokkaido region). 21th largest island in the world.

Astrology

Distances between cities

  • There is a 14 miles (21 km) direct distance between Bogor (Indonesia) and Depok (Indonesia).
  • There is a 14 miles (21 km) direct distance between Dombivli (India) and Navi Mumbai (India).
  • There is a 14 miles (21 km) direct distance between Ecatepec (Mexico) and Mexico City (Mexico).

Games

  • 21 is a player's highest score in a hand of Blackjack or Twenty-one.
  • Pokémon Spearow (Onisuzume) is a Pokémon number # 021 of the National Pokédex. Spearow is a normal, flying type Pokémon in the first generation. It is a Flying Egg group Pokémon. Spearow's other indexes are Kalos Centro index 109 - Highland Pokédex, Johto index 013 .

In other fields

  • Dreaming of the number 21 means transmuting all of the above for spiritual balance, if this number repeats itself in time it is a good sign that you are achieving it.

Mathematics

  • 21 is the smallest number of distinct squares needed to tile a square.

Music

  • '21 Seconds' is a song from the acronym of the British garage So Solid Crew.
  • '21 Questions ', in Spanish '21 questions', is a song performed by 50 Cent, an American rapper and businessman.
  • '21' is the debut single from The Paddingtons. '21' is also a song recorded by American singer Hunter Hayes.
  • '21 Guns ', in Spanish '21 armas de fuego', is a song by the American punk rock band Green Day.
  • '21 (Moon Water) 'is a song by the North American indie band Bon Iver.
  • '21 Summer ', in Spanish '21 Verano', is a song by the American country music duo Brothers Osborne.
  • '21 Savage 'is an American rapper, singer and songwriter. His name is Shyjah Joseph (Decatur, Georgia, October 22, 1992).

Science

  • Scandium is the chemical element in the periodic table that has the symbol Sc and atomic number 21.

Sports

  • The best athletes to wear number 21
    Roberto Clemente, MLB; Tim Duncan, NBA; Warren Spahn, MLB; LaDainian Tomlinson, NFL; Sammy Sosa, MLB; David Pearson, NASCAR; Roger Clemens, MLB; Deion Sanders, NFL

Tv, movies and cinematography

  • Movie: 21 Days Together Year: 1940 Runtime: 72 Director: Basil Dean With: Vivien Leigh; Leslie banks
  • Film: 21 Grams (21 Grams) Year: 2003 Duration: 125 Director: Alejandro González Inárritu With: Sean Penn; Benicio, the bull
  • Film: '21 blackjack '(English title: 21) is a 2008 film directed by Robert Luketic and starring Jim Sturgess, Kevin Spacey, Kate Bosworth and Laurence Fishburne.

Number 21 in other languages

How to say or write the number twenty-one in Spanish, German, French and other languages.
Spanish: 🔊 (número 21)

veintiuno

German: 🔊 (Anzahl 21)

einundzwanzig

French: 🔊 (nombre 21)

vingt et un

Portuguese: 🔊 (número 21)

vinte e um

Chinese: 🔊 (数 21)

二十一

Arabian: 🔊 (عدد 21)

واحد و عشرون

Czech: 🔊 (číslo 21)

dvacet jedna

Korean: 🔊 (번호 21)

이십일

Danish: 🔊 (nummer 21)

enogtyve

Hebrew: (מספר 21)

עשרים ואחד

Dutch: 🔊 (nummer 21)

eenentwintig

Japanese: 🔊 (数 21)

二十一

Indonesian: 🔊 (jumlah 21)

dua puluh satu

Italian: 🔊 (numero 21)

ventiuno

Norwegian: 🔊 (nummer 21)

tjue-en

Polish: 🔊 (liczba 21)

dwadzieścia jeden

Russian: 🔊 (номер 21)

двадцать один

Turkish: 🔊 (numara 21)

yirmibir

Thai: 🔊 (จำนวน 21)

ยี่สิบเอ็ด

Ukrainian: 🔊 (номер 21)

двадцять одна

Vietnamese: 🔊 (con số 21)

hai mươi mốt

Other languages ...

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Number 21 in News

BBC: Euros On This Day - 21 June: Goalfest in Bruges, Roo beauty & pain for Spain
BBC Sport rounds up the best archive action from 21 June in European Championship history.
June 21, 2021
BBC: Lockdown easing: Four numbers to look for ahead of the 21 June decision
The key numbers that offer clues as to whether "freedom day" will proceed as planned on 21 June.
June 8, 2021
BBC: Covid-19: Hospital data key to 21 June lockdown end, says Raab
Dominic Raab says the decision depends on breaking the link between cases and hospital admissions.
June 13, 2021
CNN: Ghana court denies bail for 21 detained LGBT activists
A Ghanaian court on Tuesday denied bail to 21 gay rights activists arrested nearly three weeks ago for what police described as an unlawful gathering, their lawyer said.
June 9, 2021
BBC: Covid-19: Government 'open' to delaying 21 June England lockdown end date
Matt Hancock says 21 June is a "not before" date for ending England's remaining restrictions.
June 6, 2021

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