18172509568 has 64 divisors (see below), whose sum is σ = 38231823600. Its totient is φ = 8580169728.

The previous prime is 18172509547. The next prime is 18172509571. The reversal of 18172509568 is 86590527181.

It is a tau number, because it is divible by the number of its divisors (64).

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, 749280 + ... + 773152.

Almost surely, 2^18172509568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18172509568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19115911800).

18172509568 is an abundant number, since it is smaller than the sum of its proper divisors (20059314032).

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

18172509568 is a wasteful number, since it uses less digits than its factorization.

18172509568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24219 (or 24207 counting only the distinct ones).

The product of its (nonzero) digits is 1209600, while the sum is 52.

The spelling of 18172509568 in words is "eighteen billion, one hundred seventy-two million, five hundred nine thousand, five hundred sixty-eight".