Twenty-one
Twenty-one | |
---|---|
21st | |
presentation | |
Roman | XXI |
dual | 1 0101 |
Octal | 25th |
Duodecimal | 19th |
Hexadecimal | 15th |
Morse code | · · - - - · - - - - |
Chinese | 二十 一 |
Mathematical properties | |
sign | positive |
parity | odd |
Factorization | |
Divider | 1, 3, 7, 21 |
The twenty-one (21) is the natural number between twenty and twenty-two . It's odd .
Math
- Twenty-one is the number between thirteen and thirty-four in the Fibonacci sequence .
- 21 is a triangular number :
- 21 is the smallest odd group order of a non-Abelian group .
- Twenty-one is the smallest positive natural number for which squares exist in pairs with different positive edge lengths, which can be put together to form a square, see squaring of the square .
Culture and society
- 21 is an American film drama from the year 2008 .
- 21 is the second album by the British singer Adele .
- 21 is the twenty-first studio album by the German power metal band Rage .
- 21 is the numeric code for the Blue Angels MC motorcycle club
- Quiz 21 is a quiz broadcast format developed by NBC as "twenty-one".
- 21 Savage is a British rapper
Web links
Commons : Twenty-one - collection of images, videos, and audio files
Wiktionary: twenty-one - explanations of meanings, word origins, synonyms, translations