165520513566 has 96 divisors (see below), whose sum is σ = 385188848928. Its totient is φ = 51185203200.

The previous prime is 165520513553. The next prime is 165520513597. The reversal of 165520513566 is 665315025561.

165520513566 is a `hidden beast` number, since 1 + 6 + 55 + 20 + 5 + 13 + 566 = 666.

It is a super-2 number, since 2×165520513566² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7003866 + ... + 7027458.

It is an arithmetic number, because the mean of its divisors is an integer number (4012383843).

Almost surely, 2^165520513566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165520513566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (192594424464).

165520513566 is an abundant number, since it is smaller than the sum of its proper divisors (219668335362).

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

165520513566 is a wasteful number, since it uses less digits than its factorization.

165520513566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23946 (or 23943 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 45.

The spelling of 165520513566 in words is "one hundred sixty-five billion, five hundred twenty million, five hundred thirteen thousand, five hundred sixty-six".