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22 (number)

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(Redirected from 22nd) Natural number
← 21 22 23 →
20 21 22 23 24 25 26 27 28 29 0 10 20 30 40 50 60 70 80 90
Cardinaltwenty-two
Ordinal22nd
(twenty-second)
Factorization2 × 11
Divisors1, 2, 11, 22
Greek numeralΚΒ´
Roman numeralXXII, xxii
Binary101102
Ternary2113
Senary346
Octal268
Duodecimal1A12
Hexadecimal1616

22 (twenty-two) is the natural number following 21 and preceding 23.

In Mathematics

22 is a semiprime, a Smith number, and an Erdős–Woods number. 22 7 = 3.14 28 {\displaystyle {\frac {22}{7}}=3.14{\color {red}28}\ldots } is a commonly used approximation of the irrational number π, the ratio of the circumference of a circle to its diameter.

22 can read as "two twos", which is the only fixed point of John Conway's look-and-say function.

The number 22 appears prominently within sporadic groups. The Mathieu group M22 is one of 26 sporadic finite simple groups, defined as the 3-transitive permutation representation on 22 points. There are also 22 regular complex apeirohedra.

In other fields

In culture and religion

In weights and measures

In other uses

Twenty-two may also refer to:

  • In French jargon, "22" is used as a phrase to warn of the coming of the police (typically "22, v'là les flics !" (In English: "5-0! Cops!")
  • In Spanish lottery and bingo, 22 is nicknamed los dos patitos, 'the two little ducks' after its shape.

See also

Notes

References

  1. Sloane, N. J. A. (ed.). "Sequence A001358". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  2. Sloane, N. J. A. (ed.). "Sequence A006753 (Smith numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
  3. Sloane, N. J. A. (ed.). "Sequence A059756 (Erdős-Woods numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
  4. Sloane, N. J. A. (ed.). "Sequence A010861 (Look-and-say constant sequence 22)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-07-21.
  5. Weisstein, Eric W. "Mathieu Groups". mathworld.wolfram.com. Retrieved 2022-07-02.
  6. Coxeter, H.S.M. (1991), Regular Complex Polytopes, Cambridge University Press, p. 140, ISBN 0-521-39490-2
  7. "Definition of CATCH-22". www.merriam-webster.com. Retrieved 2020-08-12.
  8. Sharp, Damian (2001). Simple Numerology: A Simple Wisdom book (A Simple Wisdom Book series). Red Wheel. p. 7. ISBN 978-1-57324-560-9.
  9. "Definition of CHAIN". www.merriam-webster.com. Retrieved 2020-08-19. a unit of length equal to 66 feet
  10. Cuartas, Javier (1990-01-05). "La suerte de los dos patitos" [The luck of the two little ducks]. El País (in Spanish). Oviedo. Retrieved 17 September 2020.
  11. Sanz, Elena (26 April 2010). "Los dos patitos, la niña bonita, la mala pata..." Muy Interesante (in Spanish). Retrieved 17 September 2020. Lo más normal es que el nombre tuviera que ver con la forma del número. Por ejemplo, el 11 era las banderillas, y el 22, los dos patitos o las monjas arrodilladas.

External links

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