165971520 has 504 divisors, whose sum is σ = 696114432. Its totient is φ = 35942400.

The previous prime is 165971513. The next prime is 165971537. The reversal of 165971520 is 25179561.

165971520 is a `hidden beast` number, since 1 + 65 + 9 + 71 + 520 = 666.

It is a super-2 number, since 2×165971520² = 55093090902220800, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 5353905 + ... + 5353935.

Almost surely, 2^165971520 is an apocalyptic number.

165971520 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 165971520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (348057216).

165971520 is an abundant number, since it is smaller than the sum of its proper divisors (530142912).

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

165971520 is a wasteful number, since it uses less digits than its factorization.

165971520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 18900, while the sum is 36.

The square root of 165971520 is about 12882.9934409670. The cubic root of 165971520 is about 549.5550340461. Note that the first 3 decimals are identical.

The spelling of 165971520 in words is "one hundred sixty-five million, nine hundred seventy-one thousand, five hundred twenty".