60 (number)

60 is the natural number following 59 and preceding 61.

In mathematics

Sixty is a composite number with divisors 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, making it also a highly composite number. Because 60 is the sum of its unitary divisors (excluding itself), it is a unitary perfect number. And because it is divisible by the sum of its digits in base 10, it is a Harshad number. 60 is the smallest number divisible by the numbers 1 to 6. (There is no smaller number divisible by the numbers 1 to 5).

This number is the sum of a pair of twin primes (29 + 31), as well as the sum of four consecutive primes (11 + 13 + 17 + 19).

The smallest non-abelian simple group has order 60.

In normal space, the 3 interior angles of an equilateral triangle each measure 60 degrees, adding up to 180 degrees.

The Babylonian number system had a base of sixty. A number system with base sixty is called a sexagesimal number system.

The Sexagesimal cycle plays a role in Chinese numbering and numerology.

In astronomy

• Messier object M60, a magnitude 10.5 galaxy in the constellation Virgo
• The New General Catalogue object NGC 60, a spiral galaxy in the constellation Pisces
• The Saros number of the solar eclipse series which began on -1020 May 18 and ended on 260 June 26. The duration of Saros series 60 was 1280.1 years, and it contained 72 solar eclipses. The Saros number of the lunar eclipse series which began on -700 March 8 and ended on 616 May 7. The duration of Saros series 60 was 1316.2 years, and it contained 74 lunar eclipses.

In other fields

Sixty is also:

• The atomic number of neodymium, a lanthanide
• in the measurement of time, the number of seconds in a minute, and the number of minutes in an hour.
• in geometry, the number of seconds in a minute, and the number of minutes in a degree.
• the number of the European route E60 from Brest, France to Constanta, Romania
• a common speed limit, in miles per hour, for freeways in many US states.
• in years of marriage, the diamond wedding anniversary.
• the maximum number of marbles (game pieces) in Chinese checkers.
• the code for international direct dial calls to Malaysia.
• The year AD 60, 60 BC, or 1960.