18991656728 has 32 divisors (see below), whose sum is σ = 40099691520. Its totient is φ = 8354100000.

The previous prime is 18991656683. The next prime is 18991656737. The reversal of 18991656728 is 82765619981.

It is a Harshad number since it is a multiple of its sum of digits (62).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3478148 + ... + 3483603.

It is an arithmetic number, because the mean of its divisors is an integer number (1253115360).

Almost surely, 2^18991656728 is an apocalyptic number.

It is an amenable number.

18991656728 is an abundant number, since it is smaller than the sum of its proper divisors (21108034792).

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

18991656728 is a wasteful number, since it uses less digits than its factorization.

18991656728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6961799 (or 6961795 counting only the distinct ones).

The product of its digits is 13063680, while the sum is 62.

The spelling of 18991656728 in words is "eighteen billion, nine hundred ninety-one million, six hundred fifty-six thousand, seven hundred twenty-eight".