31020640 has 48 divisors (see below), whose sum is σ = 83758752. Its totient is φ = 10635264.

The previous prime is 31020623. The next prime is 31020653. The reversal of 31020640 is 4602013.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12729 + ... + 14968.

It is an arithmetic number, because the mean of its divisors is an integer number (1744974).

Almost surely, 2^31020640 is an apocalyptic number.

It is an amenable number.

31020640 is an abundant number, since it is smaller than the sum of its proper divisors (52738112).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31020640 is a wasteful number, since it uses less digits than its factorization.

31020640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27719 (or 27711 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 31020640 is about 5569.6175811271. The cubic root of 31020640 is about 314.2077681554.

Adding to 31020640 its reverse (4602013), we get a palindrome (35622653).

The spelling of 31020640 in words is "thirty-one million, twenty thousand, six hundred forty".