18681391868 has 12 divisors (see below), whose sum is σ = 34615520352. Its totient is φ = 8791243200.

The previous prime is 18681391853. The next prime is 18681391873. The reversal of 18681391868 is 86819318681.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 137363108 + ... + 137363243.

It is an arithmetic number, because the mean of its divisors is an integer number (2884626696).

Almost surely, 2^18681391868 is an apocalyptic number.

It is an amenable number.

18681391868 is a deficient number, since it is larger than the sum of its proper divisors (15934128484).

18681391868 is a wasteful number, since it uses less digits than its factorization.

18681391868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274726372 (or 274726370 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 59.

The spelling of 18681391868 in words is "eighteen billion, six hundred eighty-one million, three hundred ninety-one thousand, eight hundred sixty-eight".