# 50 (number)

50 (number)

This article discusses the number fifty. For the year 50 CE, see 50. For other uses of 50, see 50 (disambiguation)

50
Cardinal fifty
Ordinal 50th
(fiftieth)
Numeral system quinquagesimal
Factorization $2 \cdot 5^2$
Divisors 1, 2, 5, 10, 25, 50
Roman numeral L
Unicode symbol(s)
Binary 1100102
Octal 628
Duodecimal 4212

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

## In mathematics

Fifty is the smallest number that is the sum of two non-zero square numbers in two distinct ways: 50 = 12 + 72 = 52 + 52.[1] It is also the sum of three squares, 50 = 32 + 42 + 52. It is a Harshad number.

There is no solution to the equation φ(x) = 50, making 50 a nontotient. Nor is there a solution to the equation x - φ(x) = 50, making 50 a noncototient.

The aliquot sum of 50 is 43 and its aliquot sequence is (50,43,1,0). Fifty is itself the aliquot sum of 40 and 94.

## In other fields

Fifty is:

• There are 50 states in the United States of America. The TV show Hawaii Five-O is so called because Hawaii is the 50th state[citation needed]
• 5-O (Five-Oh) - Slang for police officers and/or a warning that police are approaching. Derived from the television show Hawaii Five-O[citation needed]
• A calibre of ammunition (0.50 inches: see .50 BMG)
• In millimeters, 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
• Nickname 50 Cent, a rapper.
• A Canadian brand of beer called 50 Ale created in 1950 by Labatt breweries to commemorate 50 years of partnership. It is a popular brand still sold today.

## References

1. ^ de Koninck, J.M. (2009). Those fascinating numbers. AMS Bookstore. p. 18. ISBN 0-8218-4807-0.

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