165515918544 has 120 divisors (see below), whose sum is σ = 476638287840. Its totient is φ = 53587489536.

The previous prime is 165515918539. The next prime is 165515918597. The reversal of 165515918544 is 445819515561.

165515918544 is a `hidden beast` number, since 1 + 6 + 5 + 5 + 1 + 5 + 91 + 8 + 544 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1033702 + ... + 1183034.

It is an arithmetic number, because the mean of its divisors is an integer number (3971985732).

Almost surely, 2^165515918544 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 165515918544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (238319143920).

165515918544 is an abundant number, since it is smaller than the sum of its proper divisors (311122369296).

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

165515918544 is a wasteful number, since it uses less digits than its factorization.

165515918544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149569 (or 149560 counting only the distinct ones).

The product of its digits is 4320000, while the sum is 54.

The spelling of 165515918544 in words is "one hundred sixty-five billion, five hundred fifteen million, nine hundred eighteen thousand, five hundred forty-four".