Thirty

This article is about the number. For the year AD 30, see 30.

Thirty (30) is the natural number following twenty-nine and preceding thirty-one. This article discusses notable facts about the number 30 and then other numbers in the thirties that lack their own article.

Thirty is a composite number, its proper divisors being 1, 2, 3, 5, 6, 10, and 15.

The Roman numeral for thirty is XXX.

The Chinese word numeral for thirty is 三十.

A polygon with thirty sides is a tricegon. [1]

See also: twenty-eight, twenty-nine, thirty, thirty-one, thirty-two, integer, list of numbers.

Table of contents

1 Numbers in the Thirties

1.1 Thirty-one
1.2 Thirty-two
1.3 Thirty-three
1.4 Thirty-four
1.5 Thirty-five
1.6 Thirty-six
1.7 Thirty-seven
1.8 Thirty-eight
1.9 Thirty-nine

Numbers in the Thirties

These sections contain facts about the number 31 through 39 for which separate articles do not exist. For the years AD 31 to AD 39, see the articles 31, 32, 23, 34, 35, 36, 37, 38 and 39.

Thirty-one

Thirty-one (31) is Prime, being the larger of a pair of Twin primes. It is the third Mersenne prime. A person who is one billion (1000000000 = 10⁹) seconds old is 31 years old (and some months).

Thirty-two

Thirty-two (32) is a power of 2, being equal to 2⁵.

In humans, a full set of adult teeth numbers numbers 32.

Thirty-three

Thirty-three (33) has its own article

Thirty-eight

Thirty-eight (38) is the number of slots on an american Roulette wheel, a factorial prime such that 38!-1 is prime, and has the property that the smallest pseudoprime base 38 is 39, one greater.

Thirty-nine

Thirty-nine (39) appears in the title of the Alfred Hitchcock film The 39 Steps.