18917935920 has 240 divisors, whose sum is σ = 72445175712. Its totient is φ = 4382760960.

The previous prime is 18917935909. The next prime is 18917935921. The reversal of 18917935920 is 2953971981.

It is a tau number, because it is divible by the number of its divisors (240).

It is not an unprimeable number, because it can be changed into a prime (18917935921) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 99675 + ... + 218565.

Almost surely, 2^18917935920 is an apocalyptic number.

18917935920 is a gapful number since it is divisible by the number (10) 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 18917935920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36222587856).

18917935920 is an abundant number, since it is smaller than the sum of its proper divisors (53527239792).

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

18917935920 is a wasteful number, since it uses less digits than its factorization.

18917935920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118940 (or 118931 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 54.

The spelling of 18917935920 in words is "eighteen billion, nine hundred seventeen million, nine hundred thirty-five thousand, nine hundred twenty".