31320331021 has 24 divisors (see below), whose sum is σ = 39619683576. Its totient is φ = 24583910400.

The previous prime is 31320331001. The next prime is 31320331037. The reversal of 31320331021 is 12013302313.

It can be written as a sum of positive squares in 4 ways, for example, as 16638162121 + 14682168900 = 128989^2 + 121170^2 .

It is not a de Polignac number, because 31320331021 - 2²³ = 31311942413 is a prime.

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 31320331021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31320331001) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 477280 + ... + 538921.

It is an arithmetic number, because the mean of its divisors is an integer number (1650820149).

Almost surely, 2^31320331021 is an apocalyptic number.

It is an amenable number.

31320331021 is a deficient number, since it is larger than the sum of its proper divisors (8299352555).

31320331021 is a wasteful number, since it uses less digits than its factorization.

31320331021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1016269 (or 1016262 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 19.

Adding to 31320331021 its reverse (12013302313), we get a palindrome (43333633334).

The spelling of 31320331021 in words is "thirty-one billion, three hundred twenty million, three hundred thirty-one thousand, twenty-one".