18938139831 has 54 divisors (see below), whose sum is σ = 30071892240. Its totient is φ = 11477733696.

The previous prime is 18938139823. The next prime is 18938139863. The reversal of 18938139831 is 13893183981.

18938139831 is a `hidden beast` number, since 189 + 381 + 3 + 9 + 83 + 1 = 666.

It is not a de Polignac number, because 18938139831 - 2³ = 18938139823 is a prime.

It is a super-2 number, since 2×18938139831² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18938139931) 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 53 ways as a sum of consecutive naturals, for example, 47702925 + ... + 47703321.

Almost surely, 2^18938139831 is an apocalyptic number.

18938139831 is a deficient number, since it is larger than the sum of its proper divisors (11133752409).

18938139831 is an equidigital number, since it uses as much as digits as its factorization.

18938139831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905 (or 492 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

The spelling of 18938139831 in words is "eighteen billion, nine hundred thirty-eight million, one hundred thirty-nine thousand, eight hundred thirty-one".