22 (number)
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Template:Infobox number 22 (twenty-two) is the natural number following 21 and preceding 23.
In mathematics
22 is a semiprime,[1] a Smith number, and an Erdős–Woods number.[2][3] is a commonly used approximation of the irrational number [[Pi|Template:Pi]], 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.[4]
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.[5] There are also 22 regular complex apeirohedra.[6]
In culture and religion
- 22 is a master number in numerology.[7]
- There are 22 cards in the Major Arcana suit of a traditional tarot card deck, though they are often numbered 0-21.
In other fields
- There are 22 genetically encoded amino acids throughout known life that generate proteins during RNA translation.[8]
- There are 22 of yards in a chain.[9]
- Catch-22 (1961), Joseph Heller's novel, and its 1970 film adaptation gave rise to the expression of logic "catch-22".[10]
- 22 equal temperament is a popular microtonal tuning temperament due to its good approximation of harmonic intervals, especially septimal intervals.
- In French jargon, "22" is used as a phrase to warn of the coming of the police (typically "Template:Lang !", in English: "5-0! Cops!")
- In Spanish lottery and bingo, 22 is nicknamed Template:Langx after its shape.[11][12]