157688731 has 4 divisors (see below), whose sum is σ = 158165464. Its totient is φ = 157212000.

The previous prime is 157688717. The next prime is 157688743. The reversal of 157688731 is 137886751.

157688731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 137886751 = 631 ⋅218521.

It is a cyclic number.

It is not a de Polignac number, because 157688731 - 2⁷ = 157688603 is a prime.

It is a super-2 number, since 2×157688731² = 49731471768780722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (157688701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 237870 + ... + 238531.

It is an arithmetic number, because the mean of its divisors is an integer number (39541366).

Almost surely, 2^157688731 is an apocalyptic number.

157688731 is a deficient number, since it is larger than the sum of its proper divisors (476733).

157688731 is an equidigital number, since it uses as much as digits as its factorization.

157688731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476732.

The product of its digits is 282240, while the sum is 46.

The square root of 157688731 is about 12557.4173698257. The cubic root of 157688731 is about 540.2567720318.

The spelling of 157688731 in words is "one hundred fifty-seven million, six hundred eighty-eight thousand, seven hundred thirty-one".