Twenty
Twenty (20) is the natural number following nineteen and preceding twenty-one. This article discusses notable facts about the number 20 and then other numbers in the twenties that lack their own article.Twenty is a composite number, its proper divisors being 1, 2, 4, 5 and 10.
Twenty is used as a radix for vigesimal number systems. It is the total number of digits on the human body, which makes it a possible candidate for a numeral system. In Roman numerals it is represented as XX.
In the old UK currency system, there were twenty shillings in a pound.
A polyhedron with twenty faces is an icosahedron.
The number 20 is used as an index in measuring visual acuity. 20/20 indicates perfect vision. When someone is able to see only after an event how things turned out, that person is often said to have had "20/20 hindsight".
Twenty is the age of majority in Japanese tradition. Someone who is exactly twenty years old is described as hatachi.
The "Twenty Year Curse" refers to the pattern of the president of the United States elected every twenty years starting with 1840 to die in office (except Reagan, who was treated with intense surgery and managed to survive a would-be assassin's bullet).
Bands with the number twenty in their name include Matchbox 20.
A group of twenty units is often referred to as a score.
A curious survival from the Celtic languages is preserved in folklore from the north of England; this is called the "Lincolnshire Score" or the Shepherd's Score. This is a tally that counts twenty units using the rhyming jingle:
- Yan, tan, tethera, pethera, pimp,
- sethera, lethera, hovera, dovera, dick,
- yanadick, tanadick, tetheradick, petheradick, bumfit,
- yanabumfit, tanabumfit, tetherabumfit, petherabumfit, jiggit.
See also: eighteen, nineteen, twenty, thirty, integer, list of numbers.
This article is about the number. For the year AD 20, see 20.
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Numbers in the Twenties
These sections contain facts about the number 21 through 29 for which separate articles do not exist. For the years AD 21 to AD 29, see the articles 21, 22, 23, 24, 25, 26, 27, 28 and 29.
Twenty-two is a composite number, its proper divisors being 1, 2 and 11.
The Major Arcana of a tarot deck contains twenty-two cards if you include the fool.
In Kabbala there are twenty-two paths between the sephiroth.
The Hebrew alphabet has twenty-two letters.
Twenty-three is the ninth prime number, the sequence continues 29, 31, 37, 41,...
23 is also:
Twenty-one (21)
(Note, this article already exists)Twenty-two
Twenty-two is the natural number following twenty-one and preceding twenty-three.Twenty-three
Twenty-three (23) is the natural number following twenty-two and preceding twenty-four.
Some users suggest, for granted further enlightenment, to study the Principia Discordia, but there might be discordant opinions.
- In Mediterranean numerology, in fact, the number "23" is often identified, instead, with some well determined anatomical parts of the human body, usually considered as symbols of peace and prosperity, and in this sense the number perpetuated its symbolic content in the famous Smorfia, the typical neapolitan divinatory art of guessing lotto's sorted numbers.
- See 23 movie for Karl Koch's work
- Number of the Illuminati
Twenty-four
Twenty-four (24) is the natural number following twenty-three and preceding twenty-five.Twenty-four is a composite number, its proper divisors being 1, 2, 3, 4, 6, 8 and 12. It is also a highly composite number.
There are twenty-four hours in a day.
There are twenty-four teeth in a perfect human child's mouth.
24-karat gold is pure gold.
The Greek alphabet has twenty-four letters in its Classical and modern form.
Twenty-five
Twenty-five (25) is the natural number following twenty-four and preceding twenty-six.
Twenty-five is a square number, being 52 = 5 × 5.
There are twenty-five cents in a quarter.
In the United States, one must be at least twenty-five to be elected to the House of Representatives. "Under 25" is a common cut-off for designating youth.
Twenty-six
Twenty-six (26) is the natural number following twenty-five and preceding twenty-seven.
Twenty-six is the number of letters in the English alphabet. In the classification of finite simple groups there are 26 sporadic groups.
Twenty-seven
Twenty-seven (27) is the natural number following twenty-six and preceding twenty-eight.
Twenty-seven is a perfect cube, being 33 = 3 × 3 × 3. A 10000-day-old person is 27 years old (and some months).
Jim Morrison, Jimi Hendrix and Kurt Cobain all died when they were twenty-seven years old.
Twenty-eight
Twenty-eight (28) is the natural number following twenty-seven and preceding twenty-nine.
Twenty-eight is the second perfect number. The next perfect number is 496.
There are twenty-eight days in the shortest month of the Gregorian calendar , February. (Except on leap years, when there are twenty-nine.)
Twenty-eight is the common name for the parrot Barnardius zonarius semitorquatus, widely distributed in Western Australia and South Australia. Its call sounds like "wenniate".
The Danish and Swedish alphabets each have 28 letters.
In neo-nazi circles to indicate Blood and Honour (28 = BH - B - second letter of the alphabet and H - the eight letter).
Twenty-nine
Twenty-nine (29) is the natural number following twenty-eight and preceding thirty.
Twenty-nine (29) is a prime number, being one of a pair of Twin primes. It is the tenth prime number, the sequence continuing 31, 37, 41, 43...
The lunar month is very close to twenty-nine days. On leap years February has 29 days.
The Finnish and Norwegian alphabets each have twenty-nine letters.
