22 (number)

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. is a commonly used approximation of the irrational number , 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

• There are 22 genetically encoded amino acids throughout known life that generate proteins during RNA translation.
• Catch-22 (1961), Joseph Heller's novel, and its 1970 film adaptation gave rise to the expression of logic "catch-22".
• 22 equal temperament is a popular microtonal tuning temperament due to its good approximation of harmonic intervals, especially septimal intervals.

In culture and religion

• 22 is a master number in numerology.
• There are 22 colored properties on a traditional Monopoly board.
• There are 22 cards in the Major Arcana suit of a traditional tarot card deck, though they are often numbered 0-21.

In weights and measures

• The number of yards in a chain.

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 "' !", in English: "5-0! Cops!")
• In Spanish lottery and bingo, 22 is nicknamed after its shape.

See also

• Catch 22 (disambiguation)

References

External links