165521520 has 120 divisors (see below), whose sum is σ = 588618576. Its totient is φ = 41539584.

The previous prime is 165521509. The next prime is 165521539. The reversal of 165521520 is 25125561.

165521520 is a `hidden beast` number, since 1 + 655 + 2 + 1 + 5 + 2 + 0 = 666.

165521520 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 super-2 number, since 2×165521520² = 54794747166220800, which 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 23 ways as a sum of consecutive naturals, for example, 5479 + ... + 19001.

Almost surely, 2^165521520 is an apocalyptic number.

165521520 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 165521520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (294309288).

165521520 is an abundant number, since it is smaller than the sum of its proper divisors (423097056).

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

165521520 is a wasteful number, since it uses less digits than its factorization.

165521520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13559 (or 13550 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 165521520 is about 12865.5167016331. The cubic root of 165521520 is about 549.0579134064.

The spelling of 165521520 in words is "one hundred sixty-five million, five hundred twenty-one thousand, five hundred twenty".