18921810912 has 24 divisors (see below), whose sum is σ = 49669753896. Its totient is φ = 6307270272.

The previous prime is 18921810857. The next prime is 18921810949. The reversal of 18921810912 is 21901812981.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

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, 98551003 + ... + 98551194.

It is an arithmetic number, because the mean of its divisors is an integer number (2069573079).

Almost surely, 2^18921810912 is an apocalyptic number.

18921810912 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

18921810912 is an abundant number, since it is smaller than the sum of its proper divisors (30747942984).

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

18921810912 is a wasteful number, since it uses less digits than its factorization.

18921810912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197102210 (or 197102202 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 42.

The spelling of 18921810912 in words is "eighteen billion, nine hundred twenty-one million, eight hundred ten thousand, nine hundred twelve".