165721968 has 30 divisors (see below), whose sum is σ = 463791744. Its totient is φ = 55240608.

The previous prime is 165721961. The next prime is 165721981. The reversal of 165721968 is 869127561.

165721968 is a `hidden beast` number, since 1 + 6 + 572 + 19 + 68 = 666.

165721968 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165721961) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 575280 + ... + 575567.

Almost surely, 2^165721968 is an apocalyptic number.

165721968 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

165721968 is an abundant number, since it is smaller than the sum of its proper divisors (298069776).

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

165721968 is a wasteful number, since it uses less digits than its factorization.

165721968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1150861 (or 1150852 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 165721968 is about 12873.3044708808. The cubic root of 165721968 is about 549.2794619672.

The spelling of 165721968 in words is "one hundred sixty-five million, seven hundred twenty-one thousand, nine hundred sixty-eight".