31640880 has 40 divisors (see below), whose sum is σ = 98087472. Its totient is φ = 8437504.

The previous prime is 31640867. The next prime is 31640887. The reversal of 31640880 is 8804613.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×31640880² = 2002290574348800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (31640887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65679 + ... + 66158.

Almost surely, 2^31640880 is an apocalyptic number.

31640880 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31640880 is an abundant number, since it is smaller than the sum of its proper divisors (66446592).

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

31640880 is a wasteful number, since it uses less digits than its factorization.

31640880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131853 (or 131847 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 31640880 is about 5625.0226666210. The cubic root of 31640880 is about 316.2880991662.

The spelling of 31640880 in words is "thirty-one million, six hundred forty thousand, eight hundred eighty".