50 (fifty) is the natural number following 49 and preceding 51.

← 49 50 51 →
Cardinalfifty
Ordinal50th
(fiftieth)
Numeral systemquinquagesimal
Factorization2 × 52
Divisors1, 2, 5, 10, 25, 50
Greek numeralΝ´
Roman numeralL
Unicode symbol(s)
Binary1100102
Ternary12123
Senary1226
Octal628
Duodecimal4212
Hexadecimal3216
ArmenianԾ
Hebrewנ / ן
Babylonian numeral𒐐
Egyptian hieroglyph𓎊

In mathematics

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50 as the sum of two non-zero squares

Fifty is the smallest number that is the sum of two non-zero square numbers in two distinct ways: 50 = 12 + 72 = 52 + 52 (the former is the sum of squares of divisors of 7).[1] It is also the sum of three squares, 50 = 32 + 42 + 52 (that feature in the smallest Pythagorean triple), and the sum of four squares, 50 = 62 + 32 + 22 + 12 (as the squares of divisors of 6).[2]

50 is a Stirling number of the first kind:   and also a Narayana number:  

There is no solution to the equation φ(x) = 50, making 50 a nontotient.[3] Nor is there a solution to the equation x − φ(x) = 50, making 50 a noncototient.[4]

Fifty is the sum of the number of faces that make up the Platonic solids (4 + 6 + 8 + 12 + 20 = 50).

In science

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In religion

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In sports

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In other fields

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Fifty is:

  • There are 50 states in the United States of America.
  • The TV show Hawaii Five-O and its reimagined version, Hawaii Five-0, are so called because Hawaii is the last (50th) of the states to officially become a state.
  • 5-O (Five-Oh) - Slang for police officers and/or a warning that police are approaching. Derived from the television show Hawaii Five-O[6]
  • A calibre of ammunition (0.50 inches: see .50 BMG)
  • In millimetres, the focal length of the normal lens in 35 mm photography
  • The percentage (50%) equivalent to one half, so that the phrase "fifty-fifty" commonly expresses something divided equally in two; in business this is often denoted as being the ultimate in equal partnership
  • In years of marriage, the gold or "golden" wedding anniversary

Businesses

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  • Fifty (outlet store) - Formerly "Fifty Outlet". Outlet stores, mostly in Spain, owned by Tendam, selling its brands e.g. Cortefiel, Springfield, and others'

See also

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References

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  1. ^ de Koninck, J.M. (2009). Those fascinating numbers. AMS Bookstore. p. 18. ISBN 0-8218-4807-0.
  2. ^ Sloane, N. J. A. (ed.). "Sequence A001157 (a(n) as sigma_2(n): sum of squares of divisors of n.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2024-07-21.
  3. ^ "Sloane's A005277 : Nonients". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  4. ^ "Sloane's A005278 : Noncotients". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  5. ^ Leviticus 25:10
  6. ^ Karen Rhodes (1 February 1997). Booking Hawaii Five-O: An Episode Guide and Critical History of the 1968–1980 Television Detective Series. McFarland. p. 265. ISBN 978-0-7864-8666-3.