18911091792 has 20 divisors (see below), whose sum is σ = 48853653920. Its totient is φ = 6303697248.

The previous prime is 18911091769. The next prime is 18911091821. The reversal of 18911091792 is 29719011981.

It is a Harshad number since it is a multiple of its sum of digits (48), and also a Moran number because the ratio is a prime number: 393981079 = 18911091792 / (1 + 8 + 9 + 1 + 1 + 0 + 9 + 1 + 7 + 9 + 2).

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, 196990492 + ... + 196990587.

It is an arithmetic number, because the mean of its divisors is an integer number (2442682696).

Almost surely, 2^18911091792 is an apocalyptic number.

18911091792 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18911091792 is an abundant number, since it is smaller than the sum of its proper divisors (29942562128).

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

18911091792 is a wasteful number, since it uses less digits than its factorization.

18911091792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393981090 (or 393981084 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 48.

The spelling of 18911091792 in words is "eighteen billion, nine hundred eleven million, ninety-one thousand, seven hundred ninety-two".