31320520021 has 16 divisors (see below), whose sum is σ = 36564134400. Its totient is φ = 26269459200.

The previous prime is 31320520013. The next prime is 31320520031. The reversal of 31320520021 is 12002502313.

It is a cyclic number.

It is not a de Polignac number, because 31320520021 - 2³ = 31320520013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31320520001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2593405 + ... + 2605453.

It is an arithmetic number, because the mean of its divisors is an integer number (2285258400).

Almost surely, 2^31320520021 is an apocalyptic number.

It is an amenable number.

31320520021 is a deficient number, since it is larger than the sum of its proper divisors (5243614379).

31320520021 is a wasteful number, since it uses less digits than its factorization.

31320520021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20004.

The product of its (nonzero) digits is 360, while the sum is 19.

The spelling of 31320520021 in words is "thirty-one billion, three hundred twenty million, five hundred twenty thousand, twenty-one".