31891431641 has 4 divisors (see below), whose sum is σ = 32189482512. Its totient is φ = 31593380772.

The previous prime is 31891431623. The next prime is 31891431679. The reversal of 31891431641 is 14613419813.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31891431641 - 2⁶ = 31891431577 is a prime.

It is a super-2 number, since 2×31891431641² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31891431541) 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 3 ways as a sum of consecutive naturals, for example, 149025275 + ... + 149025488.

It is an arithmetic number, because the mean of its divisors is an integer number (8047370628).

Almost surely, 2^31891431641 is an apocalyptic number.

It is an amenable number.

31891431641 is a deficient number, since it is larger than the sum of its proper divisors (298050871).

31891431641 is a wasteful number, since it uses less digits than its factorization.

31891431641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298050870.

The product of its digits is 62208, while the sum is 41.

The spelling of 31891431641 in words is "thirty-one billion, eight hundred ninety-one million, four hundred thirty-one thousand, six hundred forty-one".