31123131320 has 32 divisors (see below), whose sum is σ = 70211847600. Its totient is φ = 12416398848.

The previous prime is 31123131311. The next prime is 31123131323. The reversal of 31123131320 is 2313132113.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 31123131292 and 31123131301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31123131323) 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, 1011329 + ... + 1041648.

Almost surely, 2^31123131320 is an apocalyptic number.

It is an amenable number.

31123131320 is an abundant number, since it is smaller than the sum of its proper divisors (39088716280).

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

31123131320 is a wasteful number, since it uses less digits than its factorization.

31123131320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2053367 (or 2053363 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 31123131320 its reverse (2313132113), we get a palindrome (33436263433).

The spelling of 31123131320 in words is "thirty-one billion, one hundred twenty-three million, one hundred thirty-one thousand, three hundred twenty".