For the year A.D. 30, see 30.

Thirty (30, XXX) is the natural number following twenty-nine and preceeding thirty-one. It is a primorial as well as the sum of the squares of the integers 1, 2, 3 and 4. It is a sphenic number. Its divisors are 1, 2, 3, 5, 6, 10, 15 and 30; its factorisation is

The Chinese word numeral for thirty is 三十; a polygon with thirty sides is called a tricegon. [1]

Thirty is also:

Thirty appears in the following names and titles:
  • Thirty odd foot of grunts, the band fronted by actor Russell Crowe

List of numbers

Twenty-eight - Twenty-nine - Thirty - Thirty-one - Thirty-two