31937621521 has 27 divisors (see below), whose sum is σ = 35331067569. Its totient is φ = 28856822592.

The previous prime is 31937621519. The next prime is 31937621533. The reversal of 31937621521 is 12512673913.

The square root of 31937621521 is 178711.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 13523131521 + 18414490000 = 116289^2 + 135700^2 .

It is not a de Polignac number, because 31937621521 - 2¹ = 31937621519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31937121521) 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 26 ways as a sum of consecutive naturals, for example, 137071221 + ... + 137071453.

Almost surely, 2^31937621521 is an apocalyptic number.

31937621521 is the 178711-st square number.

31937621521 is the 89356-th centered octagonal number.

It is an amenable number.

31937621521 is a deficient number, since it is larger than the sum of its proper divisors (3393446048).

31937621521 is an frugal number, since it uses more digits than its factorization.

31937621521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610 (or 305 counting only the distinct ones).

The product of its digits is 68040, while the sum is 40.

The spelling of 31937621521 in words is "thirty-one billion, nine hundred thirty-seven million, six hundred twenty-one thousand, five hundred twenty-one".