75 is the natural number following 74 and preceding 76.

Cardinal	seventy-five
Ordinal	75th (seventy-fifth)
Factorization
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.