18131581836 has 24 divisors (see below), whose sum is σ = 47007805040. Its totient is φ = 6043860576.

The previous prime is 18131581813. The next prime is 18131581843. The reversal of 18131581836 is 63818513181.

18131581836 is a `hidden beast` number, since 1 + 8 + 1 + 31 + 581 + 8 + 36 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 18131581791 and 18131581800.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 83942401 + ... + 83942616.

Almost surely, 2^18131581836 is an apocalyptic number.

It is an amenable number.

18131581836 is an abundant number, since it is smaller than the sum of its proper divisors (28876223204).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18131581836 is a wasteful number, since it uses less digits than its factorization.

18131581836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167885030 (or 167885022 counting only the distinct ones).

The product of its digits is 138240, while the sum is 45.

The spelling of 18131581836 in words is "eighteen billion, one hundred thirty-one million, five hundred eighty-one thousand, eight hundred thirty-six".