31375721620 has 24 divisors (see below), whose sum is σ = 65911422024. Its totient is φ = 12546020736.

The previous prime is 31375721603. The next prime is 31375721627. The reversal of 31375721620 is 2612757313.

It can be written as a sum of positive squares in 4 ways, for example, as 1312323076 + 30063398544 = 36226^2 + 173388^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 31375721620.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31375721627) 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, 206127 + ... + 324406.

It is an arithmetic number, because the mean of its divisors is an integer number (2746309251).

Almost surely, 2^31375721620 is an apocalyptic number.

It is an amenable number.

31375721620 is an abundant number, since it is smaller than the sum of its proper divisors (34535700404).

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

31375721620 is a wasteful number, since it uses less digits than its factorization.

31375721620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533499 (or 533497 counting only the distinct ones).

The product of its (nonzero) digits is 52920, while the sum is 37.

The spelling of 31375721620 in words is "thirty-one billion, three hundred seventy-five million, seven hundred twenty-one thousand, six hundred twenty".