138 (number)

 ← 137 138 139 →
Cardinal one hundred thirty-eight
Ordinal 138th
(one hundred and thirty-eighth)
Factorization 2 × 3 × 23
Divisors 1, 2, 3, 6, 23, 46, 69, 138
Roman numeral CXXXVIII
Binary 100010102
Ternary 120103
Quaternary 20224
Quinary 10235
Senary 3506
Octal 2128
Duodecimal B612
Vigesimal 6I20
Base 36 3U36

138 (one hundred [and] thirty-eight) is the natural number following 137 and preceding 139.

In mathematics

138 is a sphenic number, the sum of four consecutive primes (29 + 31 + 37 + 41), and the smallest product of 3 primes, such that in base 10, the third prime is a concatenation of the other two: ${\displaystyle 2\cdot 3\cdot 23}$.

138 is the third 47-gonal number[1] and an Ulam number,[2] as well as a 1 step palindrome (138 + 831 = 969.)

138 is the 72nd normal Congruent number [3] and the 49th primitive or square free congruent number.[4]

In media

• American singer Glenn Danzig wrote a song entitled "We are 138", recorded in 1978 by the Misfits, and reputedly inspired by the George Lucas film THX-1138.
• 1.3.8., a compilation by slam metal band Devourment
• 138 is a commonly used tempo in trance music, specifically uplifting trance music. Armin van Buuren created a song called "Who's Afraid of 138?!" as a reference to this. This also led to a record label being created by Armin van Buuren also called "Who's Afraid of 138?!" and is currently a sublabel of Armada Music

138 is also: