18691311808 has 28 divisors (see below), whose sum is σ = 39943694560. Its totient is φ = 8626758912.

The previous prime is 18691311781. The next prime is 18691311817. The reversal of 18691311808 is 80811319681.

It is a super-3 number, since 3×18691311808³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11231928 + ... + 11233591.

It is an arithmetic number, because the mean of its divisors is an integer number (1426560520).

Almost surely, 2^18691311808 is an apocalyptic number.

It is an amenable number.

18691311808 is an abundant number, since it is smaller than the sum of its proper divisors (21252382752).

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

18691311808 is a wasteful number, since it uses less digits than its factorization.

18691311808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22465544 (or 22465534 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 46.

The spelling of 18691311808 in words is "eighteen billion, six hundred ninety-one million, three hundred eleven thousand, eight hundred eight".