166565520 has 120 divisors (see below), whose sum is σ = 610264512. Its totient is φ = 40377600.

The previous prime is 166565513. The next prime is 166565569. The reversal of 166565520 is 25565661.

It is a happy number.

166565520 is a `hidden beast` number, since 16 + 65 + 65 + 520 = 666.

166565520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (120).

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

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, 2596 + ... + 18435.

Almost surely, 2^166565520 is an apocalyptic number.

166565520 is a gapful number since it is divisible by the number (10) 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 166565520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (305132256).

166565520 is an abundant number, since it is smaller than the sum of its proper divisors (443698992).

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

166565520 is a wasteful number, since it uses less digits than its factorization.

166565520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21061 (or 21052 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The square root of 166565520 is about 12906.0264992754. The cubic root of 166565520 is about 550.2098593093.

The spelling of 166565520 in words is "one hundred sixty-six million, five hundred sixty-five thousand, five hundred twenty".