31881618813 has 24 divisors (see below), whose sum is σ = 46734552928. Its totient is φ = 19318068000.

The previous prime is 31881618773. The next prime is 31881618833.

31881618813 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 31881618813 - 2⁶ = 31881618749 is a prime.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31881618833) 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, 3295203 + ... + 3304863.

Almost surely, 2^31881618813 is an apocalyptic number.

31881618813 is a gapful number since it is divisible by the number (33) formed by its first and last digit.

It is an amenable number.

31881618813 is a deficient number, since it is larger than the sum of its proper divisors (14852934115).

31881618813 is a wasteful number, since it uses less digits than its factorization.

31881618813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18777 (or 18766 counting only the distinct ones).

The product of its digits is 221184, while the sum is 48.

The spelling of 31881618813 in words is "thirty-one billion, eight hundred eighty-one million, six hundred eighteen thousand, eight hundred thirteen".