31403920 has 20 divisors (see below), whose sum is σ = 73014300. Its totient is φ = 12561536.

The previous prime is 31403893. The next prime is 31403921. The reversal of 31403920 is 2930413.

It can be written as a sum of positive squares in 2 ways, for example, as 18558864 + 12845056 = 4308^2 + 3584^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 31403891 and 31403900.

It is not an unprimeable number, because it can be changed into a prime (31403921) 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, 196195 + ... + 196354.

It is an arithmetic number, because the mean of its divisors is an integer number (3650715).

Almost surely, 2^31403920 is an apocalyptic number.

It is an amenable number.

31403920 is an abundant number, since it is smaller than the sum of its proper divisors (41610380).

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

31403920 is a wasteful number, since it uses less digits than its factorization.

31403920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392562 (or 392556 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 31403920 is about 5603.9200565319. The cubic root of 31403920 is about 315.4965545387.

It can be divided in two parts, 31403 and 920, that added together give a palindrome (32323).

The spelling of 31403920 in words is "thirty-one million, four hundred three thousand, nine hundred twenty".