31213916 has 12 divisors (see below), whose sum is σ = 54735240. Its totient is φ = 15575280.

The previous prime is 31213913. The next prime is 31213939. The reversal of 31213916 is 61931213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5630 + ... + 9701.

It is an arithmetic number, because the mean of its divisors is an integer number (4561270).

Almost surely, 2^31213916 is an apocalyptic number.

It is an amenable number.

31213916 is a deficient number, since it is larger than the sum of its proper divisors (23521324).

31213916 is a wasteful number, since it uses less digits than its factorization.

31213916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15844 (or 15842 counting only the distinct ones).

The product of its digits is 972, while the sum is 26.

The square root of 31213916 is about 5586.9415604604. The cubic root of 31213916 is about 314.8589811379.

The spelling of 31213916 in words is "thirty-one million, two hundred thirteen thousand, nine hundred sixteen".