31640938641 has 27 divisors (see below), whose sum is σ = 49500526257. Its totient is φ = 19467077760.

The previous prime is 31640938619. The next prime is 31640938643. The reversal of 31640938641 is 14683904613.

The square root of 31640938641 is 177879.

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 8899092225 + 22741846416 = 94335^2 + 150804^2 .

It is a de Polignac number, because none of the positive numbers 2^k-31640938641 is a prime.

It is a super-2 number, since 2×31640938641² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31640938643) 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, 6935001 + ... + 6939561.

Almost surely, 2^31640938641 is an apocalyptic number.

31640938641 is the 177879-th square number.

31640938641 is the 88940-th centered octagonal number.

It is an amenable number.

31640938641 is a deficient number, since it is larger than the sum of its proper divisors (17859587616).

31640938641 is an frugal number, since it uses more digits than its factorization.

31640938641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9154 (or 4577 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The spelling of 31640938641 in words is "thirty-one billion, six hundred forty million, nine hundred thirty-eight thousand, six hundred forty-one".