51 (number)

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51 (fifty-one) is the natural number 51 following 50 and preceding 52.


Cardinal 51
fifty-one
Ordinal 51st
fifty-first
Factorization 3\cdot 17
Divisors 1, 3, 17, 51
Roman numeral LI
Binary 110011
Hexadecimal 33
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[edit] In mathematics

Fifty-one is the 14th discrete biprime and the 5th in the {3.q} semiprime family having the prime factors (3.17). The aliquot sum of 51 is 21, itself a discrete biprime. 51 is the 4th member of the 11-aliquot tree with the sequence(51,21,11,1,0)

51 is a pentagonal number as well as a centered pentagonal number (one of the few numbers to be both) and an 18-gonal number and a Perrin number. It is also the 6th Motzkin number, telling the number of ways to draw non-intersecting chords between any six points on a circle's boundary, no matter where the points may be located on the boundary.

Since the greatest prime factor of 512 + 1 = 2602 is 1301, which is clearly more than 51 twice, 51 is a Størmer number.

[edit] In science

[edit] Astronomy

[edit] In sports

[edit] In other fields

Fifty-one is:

  • The code for international direct dial phone calls to Peru
  • The model number of the P-51 Mustang WWII fighter aircraft
  • Area 51, a parcel of U.S. military-controlled land in southern Nevada, apparently containing a secret aircraft testing facility
  • Part of the title of a collection of stories by Lord Dunsany, Fifty-One Tales
  • The number of the fire station and rescue squad in the TV series Emergency!
  • The number of Rowdy Burns's car (Michael Rooker), later Cole Trickle's (Tom Cruise) number in the film Days of Thunder
  • Washington D.C. and Puerto Rico often mentioned as the future "51st State"
  • Owning 51% of stocks makes one a major shareholder
  • Samuel L. Jackson starred in "Formula 51” "a.k.a. “51st State"
  • "Paul is Live" album (1993): Paul McCartney's cover shot in front of London's Abbey Road Studios. A parody of the original Abbey Road. Paul, then 51, is wearing shoes, and the Volkswagen bears a license plate that reads "51 IS" (instead of "28 IF" as on Abbey Road).
  • "51st anniversary" song by Jimi Hendrix
  • "Come in Number 51, Your Time is Up" song by Pink Floyd
  • Bob Dylan: Highway 51 Blues and the name of a band
  • The Parker 51, introduced in 1941, may well be the most famous fountain pen ever made
  • A brand of pastis (anise liqueur) manufactured by Pernod Ricard
  • "Cachaça 51" is the brand name of a cachaça produced by a Companhia Müller de Bebidas in Pirassununga, São Paulo, Brasil.
  • Video games Designer Goichi Suda uses 51 in his nickname (Suda51) as a play on words with his name (Goichi, GO translates to 5, and ICHI to 1)
  • In some circles, 51 signifies peace, respect, unity, and family.
  • The 51 hand gesture can be made by holding 5 fingers up in the right hand and 1 finger in the right hand.
  • The Area 51 nightclub in Williamsburg, Brooklyn is referring to this usage of 51, and not the Air Force facility.
  • Throughout some local communities in Romania, "51" means "Screw U!" (Screw - 5 characters; U - 1 character)
  • The '51 is a guitar made by Fender's second brand, Squier. It is notable for being one of only a few original models produced by the marque.

[edit] Historical years

51 A.D., 51 B.C., 1951, 2051, etc.