31312997520 has 80 divisors (see below), whose sum is σ = 110937482880. Its totient is φ = 7157256192.

The previous prime is 31312997461. The next prime is 31312997539. The reversal of 31312997520 is 2579921313.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9317665 + ... + 9321024.

It is an arithmetic number, because the mean of its divisors is an integer number (1386718536).

Almost surely, 2^31312997520 is an apocalyptic number.

31312997520 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31312997520 is an abundant number, since it is smaller than the sum of its proper divisors (79624485360).

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

31312997520 is a wasteful number, since it uses less digits than its factorization.

31312997520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18638712 (or 18638706 counting only the distinct ones).

The product of its (nonzero) digits is 102060, while the sum is 42.

The spelling of 31312997520 in words is "thirty-one billion, three hundred twelve million, nine hundred ninety-seven thousand, five hundred twenty".