Number 21
Number 21 is said 🔊, write in letters as follows: twentyone . Ordinal number 21th is said 🔊 and write: twentyfirst. The meaning of number 21: Basic maths, advanced mathematics and properties, computer science, numerology, codes and images, writing and naming in other languages, other interesting facts and comments. Number 21 in News.
Useful information about number 21
The decimal (Arabic) number 21 converted to a Roman number is XXI.
Roman and decimal number conversions.
21 kilograms (kg) = 46.3 pounds (lb)
21 pounds (lb) = 9.5 kilograms (kg)
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).
21° Fahrenheit (°F) equals to 69.8° Celsius (°C)
21° Celsius (°C) equals to 6.1° Fahrenheit (°F)
21 Horsepower (hp) equals to 15.44 kilowatts (kW)
21 kilowatts (kW) equals to 28.56 horsepower (hp)
The number 21 converted to a Mayan number is  
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 69.8° Celsius (°C)
21° Celsius (°C) equals to 6.1° 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:
Images of the number  
Image (1) of the number  Image (2) of the number 
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Number 21 infographic.

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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).
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).
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 21^{2} is 441.
The third power of 21^{3} is 9.261.
Roots
The square root √21 is 4,582576.
The cube root of ^{3}√21 is 2,758924.
Logarithms
The natural logarithm of No. ln 21 = log_{e} 21 = 3,044522.
The logarithm to base 10 of No. log_{10} 21 = 1,322219.
The Napierian logarithm of No. log_{1/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: NoIs 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 type  Code value 

Port 21/TCP  FTP Protocol (control)  port for FTP commands and flow control 
Unix time  Unix time 21 is equal to Thursday Jan. 1, 1970, 12:21 a.m. GMT 
IPv4, IPv6  Number 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 BASE64  MjE= 
21 MD5  3c59dc048e8850243be8079a5c74d079 
21 SHA1  472b07b9fcf2c2451e8781e944bf5f77cd8457c8 
More SHA codes related to the number 21 ... 
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, selfreliance 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 DC6B 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
 It is one of the lucky numbers for the zodiac sign Aries and Scorpio.
 ¿Qué es la astrología y para qué sirve?
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 Twentyone.
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.
Please write us
If you know something interesting about the number 21 or any natural number (positive integer), please write to us.Number 21 in other languages
How to say or write the number twentyone 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 
Other languages ... 
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natural number (positive integer).
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Number 21 in News
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: Covid19: 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: Covid19: 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

BBC: Covid19: Could a third wave change 21 June plans in England? Rising coronavirus cases have called the planned 21 June relaxing of rules in England into question. ... June 2, 2021
