50 (number)

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

← 50 51 52 53 54 55 56 57 58 59 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	50 fifty
Ordinal	50th fiftieth
Factorization	$2 \cdot 5^2$
Divisors	1, 2, 5, 10, 25, 50
Roman numeral	L
Roman numeral (Unicode)	L, l
Binary	110010
Octal	62
Duodecimal	42
Hexadecimal	32
Hebrew	נ (Nun)

Look up fifty in
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1 In mathematics
2 In science
- 2.1 Astronomy
3 In religion
4 In other fields
5 Sports
6 Historical years

[edit] In mathematics

Fifty is the smallest number that can be written as the sum of two squares in two distinct ways: 50 = 1² + 7² = 5² + 5². It is also the sum of three squares, 50 = 3² + 4² + 5². It is a Harshad number.

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

50 is the 7th Square-Prime with the prime structure (2.5^5). It is the 2nd inverted Square-Prime in the form (p.q^q). The Prime 43 is the aliquot sum of 50 The aliquot sequence of 50 comprises but 3 members (50,43,1) 50 is itself the aliquot sum of 40 and 94. 50 is the 4th member of the 43-aliquot prime tree, the next member being 60.

[edit] In science

The atomic number of tin
The fifth magic number in physics

[edit] Astronomy

Messier object M50, a magnitude 7.0 open cluster in the constellation Monoceros
The New General Catalogue object NGC 50, a spiral galaxy in the constellation Cetus
The Saros number of the solar eclipse series which began on 1201 February 11 BC and ended on 97 April 1. The duration of Saros series 50 was 1298.1 years, and it contained 73 solar eclipses.
The Saros number of the lunar eclipse series which began on -1134 July 3 and ended on 164 August 20. The duration of Saros series 50 was 1298.1 years, and it contained 73 lunar eclipses.

[edit] In religion

In Kabbalah, there are 50 Gates of Wisdom (or Understanding) and 50 Gates of Impurity
The traditional number of years in a jubilee period

[edit] In other fields

Fifty is:

The TV show Hawaii Five-O is so called because Hawaii is the 50th state
A gentleman's club in London
A calibre of ammunition (0.50 inches: see .50 BMG)
In millimeters, the focal length of the normal lens in 35mm 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
An event of probability one half
In years of marriage, the gold or "golden" wedding anniversary
Part of the name of 50 Cent, a rapper
The number of chapters in the book of Genesis
Kennedy Half Dollar (50 cents)
Roman Numeral: L
President Ulysses S. Grant is on the U.S. $50 bill
“Fifty Degrees Below" book by Kim Stanley Robinson”
“50 Ways to Leave Your Lover” song by Paul Simon
"50 First Dates" movie directed by Peter Segal
Fabulous 50s, a nickname for the fifties decade
Lucas Jackson ate 50 eggs in an hour in the movie "Cool Hand Luke"