31381890660 has 72 divisors (see below), whose sum is σ = 96532502976. Its totient is φ = 8250634560.

The previous prime is 31381890653. The next prime is 31381890677. The reversal of 31381890660 is 6609818313.

It is a happy number.

It is a super-2 number, since 2×31381890660² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1214994 + ... + 1240553.

It is an arithmetic number, because the mean of its divisors is an integer number (1340729208).

Almost surely, 2^31381890660 is an apocalyptic number.

31381890660 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31381890660 is an abundant number, since it is smaller than the sum of its proper divisors (65150612316).

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

31381890660 is a wasteful number, since it uses less digits than its factorization.

31381890660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2455633 (or 2455628 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 31381890660 in words is "thirty-one billion, three hundred eighty-one million, eight hundred ninety thousand, six hundred sixty".