31860640 has 48 divisors (see below), whose sum is σ = 86026752. Its totient is φ = 10923264.

The previous prime is 31860593. The next prime is 31860643. The reversal of 31860640 is 4606813.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 31860599 and 31860608.

It is not an unprimeable number, because it can be changed into a prime (31860643) 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, 13104 + ... + 15343.

It is an arithmetic number, because the mean of its divisors is an integer number (1792224).

Almost surely, 2^31860640 is an apocalyptic number.

It is an amenable number.

31860640 is an abundant number, since it is smaller than the sum of its proper divisors (54166112).

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

31860640 is a wasteful number, since it uses less digits than its factorization.

31860640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28469 (or 28461 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 31860640 is about 5644.5230090770. The cubic root of 31860640 is about 317.0186642940.

The spelling of 31860640 in words is "thirty-one million, eight hundred sixty thousand, six hundred forty".