18521730864 has 200 divisors, whose sum is σ = 65978589600. Its totient is φ = 4884820992.

The previous prime is 18521730839. The next prime is 18521730889. The reversal of 18521730864 is 46803712581.

18521730864 is a `hidden beast` number, since 18 + 521 + 7 + 30 + 86 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (18521730839) and next prime (18521730889).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 39412 + ... + 196460.

It is an arithmetic number, because the mean of its divisors is an integer number (329892948).

Almost surely, 2^18521730864 is an apocalyptic number.

18521730864 is a gapful number since it is divisible by the number (14) 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 18521730864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32989294800).

18521730864 is an abundant number, since it is smaller than the sum of its proper divisors (47456858736).

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

18521730864 is a wasteful number, since it uses less digits than its factorization.

18521730864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157089 (or 157074 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 18521730864 in words is "eighteen billion, five hundred twenty-one million, seven hundred thirty thousand, eight hundred sixty-four".