31545020521 has 12 divisors (see below), whose sum is σ = 36708771780. Its totient is φ = 27028609440.

The previous prime is 31545020501. The next prime is 31545020539. The reversal of 31545020521 is 12502054513.

It can be written as a sum of positive squares in 2 ways, for example, as 4142853225 + 27402167296 = 64365^2 + 165536^2 .

It is not a de Polignac number, because 31545020521 - 2⁵ = 31545020489 is a prime.

It is a super-2 number, since 2×31545020521² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31545020521.

It is not an unprimeable number, because it can be changed into a prime (31545020501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16875 + ... + 251743.

It is an arithmetic number, because the mean of its divisors is an integer number (3059064315).

Almost surely, 2^31545020521 is an apocalyptic number.

It is an amenable number.

31545020521 is a deficient number, since it is larger than the sum of its proper divisors (5163751259).

31545020521 is a wasteful number, since it uses less digits than its factorization.

31545020521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237624 (or 237617 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 28.

The spelling of 31545020521 in words is "thirty-one billion, five hundred forty-five million, twenty thousand, five hundred twenty-one".