18000515556 has 81 divisors (see below), whose sum is σ = 46408030851. Its totient is φ = 5882910768.

The previous prime is 18000515551. The next prime is 18000515573. The reversal of 18000515556 is 65551500081.

The square root of 18000515556 is 134166.

It is a perfect power (a square), and thus also a powerful number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 18000515556.

It is not an unprimeable number, because it can be changed into a prime (18000515551) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 47494575 + ... + 47494953.

Almost surely, 2^18000515556 is an apocalyptic number.

18000515556 is the 134166-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18000515556

18000515556 is an abundant number, since it is smaller than the sum of its proper divisors (28407515295).

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

18000515556 is an equidigital number, since it uses as much as digits as its factorization.

18000515556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 886 (or 443 counting only the distinct ones).

The product of its (nonzero) digits is 30000, while the sum is 36.

Multiplying 18000515556 by its sum of digits (36), we get a square (648018560016 = 804996²).

18000515556 divided by its sum of digits (36) gives a square (500014321 = 22361²).

The spelling of 18000515556 in words is "eighteen billion, five hundred fifteen thousand, five hundred fifty-six".