73 (number)

From Wikipedia, the free encyclopedia

73 (seventy-three) is the natural number following 72 and preceding 74. In English, it is the smallest integer with twelve letters in its spelled out name.

Cardinal 73
seventy-three
Ordinal 73rd
seventy-third
Factorization prime
Divisors 1, 73
Roman numeral LXXIII
Binary 1001001
Hexadecimal 49

Contents

[edit] In mathematics

Seventy-three is the 21st prime number. The previous is seventy-one, with which it comprises the 8th twin prime. It is also a permutable prime with thirty-seven. 73 is a star number.

Every positive integer is the sum of at most 73 sixth powers (see Waring's problem).

In base 5, the smallest prime with a composite sum of digits is 73.

73 is a repdigit in base 8 (111).

[edit] In science

In astronomy,

Messier object M73, a magnitude 9.0 apparent open cluster in the constellation Aquarius
The New General Catalogue object NGC 73, a barred spiral galaxy in the constellation Cetus
The Saros number of the solar eclipse series which began on 717 BC July 16 and ended on 582 September 3. The duration of Saros series 73 was 1298.1 years, and it contained 73 solar eclipses.
The number of seconds it took for the OV-099 shuttle to explode after launch.

[edit] In other fields

Seventy-three is also:

[edit] In sports