19891123900 has 18 divisors (see below), whose sum is σ = 43163739080. Its totient is φ = 7956449520.

The previous prime is 19891123897. The next prime is 19891123919. The reversal of 19891123900 is 932119891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 99455520 + ... + 99455719.

Almost surely, 2^19891123900 is an apocalyptic number.

19891123900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19891123900 is an abundant number, since it is smaller than the sum of its proper divisors (23272615180).

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

19891123900 is a wasteful number, since it uses less digits than its factorization.

19891123900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198911253 (or 198911246 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 43.

The spelling of 19891123900 in words is "nineteen billion, eight hundred ninety-one million, one hundred twenty-three thousand, nine hundred".