18668978928 has 160 divisors (see below), whose sum is σ = 56062126080. Its totient is φ = 5936958720.

The previous prime is 18668978879. The next prime is 18668978953. The reversal of 18668978928 is 82987986681.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4180825 + ... + 4185287.

It is an arithmetic number, because the mean of its divisors is an integer number (350388288).

Almost surely, 2^18668978928 is an apocalyptic number.

18668978928 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18668978928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28031063040).

18668978928 is an abundant number, since it is smaller than the sum of its proper divisors (37393147152).

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

18668978928 is a wasteful number, since it uses less digits than its factorization.

18668978928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4924 (or 4912 counting only the distinct ones).

The product of its digits is 167215104, while the sum is 72.

The spelling of 18668978928 in words is "eighteen billion, six hundred sixty-eight million, nine hundred seventy-eight thousand, nine hundred twenty-eight".