# 157 (number)

 ← 156 157 158 →
Cardinalone hundred fifty-seven
Ordinal157th
(one hundred and fifty-seventh)
Factorizationprime
Prime37th
Divisors1, 157
Roman numeralCLVII
Binary100111012
Ternary122113
Quaternary21314
Quinary11125
Senary4216
Octal2358
Duodecimal11112
Vigesimal7H20
Base 364D36

 ← 156 157 158 →
Cardinalone hundred fifty-seven
Ordinal157th
(one hundred and fifty-seventh)
Factorizationprime
Prime37th
Divisors1, 157
Roman numeralCLVII
Binary100111012
Ternary122113
Quaternary21314
Quinary11125
Senary4216
Octal2358
Duodecimal11112
Vigesimal7H20
Base 364D36

157 (one hundred [and] fifty-seven) is the number following 156 and preceding 158.

## In mathematics

157 is a prime number. The next prime is 163 and the previous prime is 151, with which 157 form a sexy prime triplet. Taking the arithmetic mean of those primes yields 157, thus it is a balanced prime.

In base 10, 1572 is 24649, and 1582 is 24964, which uses the same digits. 157 is the largest known number with a square that relates in this way to the square of the next integer.

157 is a repunit in base 12 (111), so it is a unique prime in the same base.

The simplest right angle triangle with rational sides that has area 157 has the longest side with a denominator of 45 digits.

157 is also an emirp, a Chen prime, and the least irregular prime with index 2.

157 is the largest known prime p which $\frac{p^p+1}{p+1}$ is also prime. (see )

157 is also: