165601971 has 12 divisors (see below), whose sum is σ = 239527080. Its totient is φ = 110251680.

The previous prime is 165601963. The next prime is 165601999. The reversal of 165601971 is 179106561.

It is a happy number.

165601971 is a `hidden beast` number, since 1 + 6 + 560 + 1 + 97 + 1 = 666.

It is not a de Polignac number, because 165601971 - 2³ = 165601963 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165601921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5241 + ... + 18938.

It is an arithmetic number, because the mean of its divisors is an integer number (19960590).

Almost surely, 2^165601971 is an apocalyptic number.

165601971 is a deficient number, since it is larger than the sum of its proper divisors (73925109).

165601971 is a wasteful number, since it uses less digits than its factorization.

165601971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24946 (or 24943 counting only the distinct ones).

The product of its (nonzero) digits is 11340, while the sum is 36.

The square root of 165601971 is about 12868.6429354458. The cubic root of 165601971 is about 549.1468547186.

The spelling of 165601971 in words is "one hundred sixty-five million, six hundred one thousand, nine hundred seventy-one".