81390737931933 has 64 divisors (see below), whose sum is σ = 116726884319232. Its totient is φ = 50325255763200.

The previous prime is 81390737931929. The next prime is 81390737931989. The reversal of 81390737931933 is 33913973709318.

It is not a de Polignac number, because 81390737931933 - 2² = 81390737931929 is a prime.

It is a super-2 number, since 2×81390737931933² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81390737931233) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 182432691 + ... + 182878287.

It is an arithmetic number, because the mean of its divisors is an integer number (1823857567488).

Almost surely, 2^{81390737931933} is an apocalyptic number.

It is an amenable number.

81390737931933 is a deficient number, since it is larger than the sum of its proper divisors (35336146387299).

81390737931933 is a wasteful number, since it uses less digits than its factorization.

81390737931933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446194.

The product of its (nonzero) digits is 69441624, while the sum is 66.

The spelling of 81390737931933 in words is "eighty-one trillion, three hundred ninety billion, seven hundred thirty-seven million, nine hundred thirty-one thousand, nine hundred thirty-three".