75 (number)
75 is the natural number following 74 and preceding 76.
| |||
| Cardinal | seventy-five | ||
| Ordinal | 75th (seventy-fifth) | ||
| Factorization | 
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| Divisors | 3, 5, 15, 25 | ||
| Roman numeral | LXXV | ||
| Binary | 1001011 | ||
| Hexadecimal | 4B | ||
In mathematics
As the sum of the first five pentagonal numbers, seventy-five is a pentagonal pyramidal number. It is also an enneagonal number.
It is also a Keith number, because it recurs in a Fibonacci-like sequence started from its base 10 digits: 7, 5, 12, 17, 29, 46, 75... But there is no integer that added up to its own digits adds up to 75, hence 75 is a self number.
There are 75 uniform polyhedra.
In science
- The atomic number of rhenium
In astronomy,
- Messier object M75, a magnitude 9.5 globular cluster in the constellation Sagittarius
- The New General Catalogue object NGC 75, a spiral galaxy in the constellation Pisces
- The Saros number of the solar eclipse series which began on -604 July 7 and ended on 694 August 26. The duration of Saros series 75 was 1298.1 years, and it contained 73 solar eclipses.
- The Saros number of the lunar eclipse series which began on -266 May 8 and ended on 1014 June 15. The duration of Saros series 75 was 1280.1 years, and it contained 72 lunar eclipses.
In other fields
Seventy-five is also:
- The designation of Interstate 75, a freeway that runs from Florida to Michigan.
- The registry of the U.S. Navy's nuclear aircraft carrier USS Harry S. Truman (CVN-75), named after U.S. President Harry S. Truman.
- The record for most game show wins, held by Ian Lygo. Also, the record for most game show appearances, currently a tie between Lygo and Ken Jennings.
- The year AD 75, 75 BC, or 1975.