1. In mathematics

2. In physics and chemistry

3. In aircraft

4. In art, entertainment, and media
    In music  In other fields 

5. In computing and technology

6. In religion

7. In sports

8. In weights and measures

9. In other uses

10. See also

11. References

12. External links

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

In mathematics

• 22 is a deficient number.
• 22 is an even composite number and a semiprime; its proper divisors are 1, 2, and 11.
• 22 is a pentagonal number^[1] and a centered heptagonal number.^[2]
• 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]
• 22 is the sum of the totient function for the first eight integers.^[5]
• 22 is a Perrin number, preceded in the sequence by 10, 12, and 17.^[6]
• 22 divided by 7 approximates the irrational number {{pi}}, the ratio of the circumference of a circle to its diameter.
• 22 is an Erdős–Woods number, since it is possible to find sequences of 22 consecutive integers such that each inner member shares a factor with either the first or the last member.^[7]
• 22 is a Smith number in base 10.^[8]
• "2-2" is the only fixed point of John Conway's look-and-say function.^[9]{{importance inline}}

In physics and chemistry

• 22 is the atomic number of titanium.

In aircraft

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

In art, entertainment, and media

In music

• "Twenty Two" is a 1997 song by the punk band Millencolin
• In Jay-Z's song "22 Two's", he rhymes the words: too, to, and two, 22 times in the first verse.
• "22 Acacia Avenue" is a song by Iron Maiden on the album The Number of the Beast
• Catch 22 is an album by death metal band Hypocrisy
• "22" is a song by Lily Allen on the album It's Not Me, It's You.
• 22 Dreams is a song and album by Paul Weller. The album contains 22 songs on it.
• The Norwegian electronica project Ugress uses 22 as a recurring theme. All four albums feature a track with 22 in the title.
• "22" is a song by Taylor Swift on her fourth album Red
• "The Number 22" is a song by Ashbury Heights on the album The Looking Glass Society.
• 22, A Million is an album by Bon Iver. The first track of the album is called "22 (OVER SOON)".
• Cubic 22 was a Belgian techno duo.
• "22" is a song by the English alternative rock band Deaf Havana on their album Old Souls
• "22" is a song by the Irish singer Sarah McTernan. She will represent Ireland with this song in Eurovision 2019.

In other fields

• Catch-22 (1961), Joseph Heller's novel, and its 1970 film 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 computing and technology

• 22 is the standard port number for the Secure Shell protocol
• A quotation mark (in a URL it appears as a "%22")

In religion

• There are 22 letters in the Hebrew alphabet.
• In the Kabbalah, there are 22 paths between the Sephirot.

In sports

• In soccer there are 22 players that start a game and the maximum number of players playing at any time.
• In Australian rules football, each team is allowed a squad of 22 players (18 on the field and 4 interchanges).
• The length of a cricket pitch is 22 yards.
• 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.
• A snooker game (called a "frame") starts with 22 coloured balls at specified locations on the table (15 red balls and 7 others).

In weights and measures

• The number of yards in a chain.

In other uses

Twenty-two may also refer to:

• 22 is the number of the French department Côtes-d'Armor
• "22" is a common name for the .22 calibre .22 Long Rifle cartridge.
• 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 photography, f/22 is the largest f-stop (and thus smallest aperture) available on most lenses made for single-lens reflex cameras

See also

• Catch 22 (disambiguation)
• List of highways numbered 22
• Synchronicity{{relevance-inline|date=November 2018}}

References

External links

• {{cite web|url=http://www.virtuescience.com/22.html|website=Virtuescience|title= The Number 22 at The Database of Number Correlations}}

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