31157618 has 6 divisors (see below), whose sum is σ = 46748271. Its totient is φ = 15574862.

The previous prime is 31157551. The next prime is 31157627. The reversal of 31157618 is 81675113.

It can be written as a sum of positive squares in only one way, i.e., 15578809 + 15578809 = 3947^2 + 3947^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3947.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 5921 + ... + 9867.

Almost surely, 2^31157618 is an apocalyptic number.

31157618 is a deficient number, since it is larger than the sum of its proper divisors (15590653).

31157618 is an frugal number, since it uses more digits than its factorization.

31157618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7896 (or 3949 counting only the distinct ones).

The product of its digits is 5040, while the sum is 32.

The square root of 31157618 is about 5581.9009306866. The cubic root of 31157618 is about 314.6695720450.

Multiplying 31157618 by its sum of digits (32), we get a square (997043776 = 31576²).

The spelling of 31157618 in words is "thirty-one million, one hundred fifty-seven thousand, six hundred eighteen".