# 22 (number)

 ← 21 22 23 →
Cardinal twenty-two
Ordinal 22nd
(twenty-second)
Factorization 2 × 11
Divisors 1, 2, 11, 22
Roman numeral XXII
Binary 101102
Ternary 2113
Quaternary 1124
Quinary 425
Senary 346
Octal 268
Duodecimal 1A12
Vigesimal 1220
Base 36 M36

22 (twenty-two) is the natural number following 21 and preceding 23. In a 24-hour clock, the twenty-second hour is in conventional language called ten or ten o'clock.

## In mathematics

22 is deficient

When cutting a circle with just six line segments, the maximum number of pieces that can be so created is 22,[3] thus 22 is a central polygonal number (see lazy caterer's sequence).[4]

## In aircraft

• 22 is the designation of the USAF stealth fighter, the F-22 Raptor.

## In art, entertainment, and media

### In other fields

• In bingo, 22 is referred to as "Two Little Ducks"
• Catch-22 (1961), Joseph Heller's novel, and its 1970 film version) by Joseph Heller, adaptation gave rise to the expression of logic "catch-22"
• Revista 22 is a magazine published in Romania
• There are 22 stars in the Paramount Pictures logo.
• "Twenty Two" (February 10, 1961) is Season 2–episode 17 (February 10, 1961) of the 1959-64 TV series The Twilight Zone, in which a hospitalized dancer has nightmares about a sinister nurse inviting her to Room 22, the hospital morgue.
• Traditional Tarot decks have 22 cards with allegorical subjects. These serve as trump cards in the game. The Fool is usually a kind of wild-card among the trumps and unnumbered, so the highest trump is numbered 21. Occult Tarot decks usually have 22 similar cards which are called Major Arcana by fortune-tellers. Occultists have related this number to the 22 letters of the Hebrew alphabet and the 22 paths in the Kabbalistic Tree of Life.

## In sports

### In American football

• 22 is the number of players on the field at any one time in an American football match

### In Australian rules football

• Each team is allowed a squad of 22 players (18 on the field and 4 interchanges).
• In the top-level Australian Football League, each team plays 22 matches in the regular (or "home-and-away") season.

### In rugby union

• The "22" is a line in each half of the field which is 22 meters from the respective try line. It has significance in a number of laws particularly relating to kicking the ball away.

## In other uses

Twenty-two may also refer to:

## References

1. ^ "Sloane's A000326 : Pentagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
2. ^ "Sloane's A069099 : Centered heptagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
3. ^ Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1986): 31
4. ^ "Sloane's A000124 : Central polygonal numbers (the Lazy Caterer's sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
5. ^ "Sloane's A002088 : Sum of totient function". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
6. ^ "Sloane's A001608 : Perrin sequence". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
7. ^ "Sloane's A059756 : Erdős-Woods numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
8. ^ "Sloane's A006753 : Smith numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.