165939939 has 48 divisors (see below), whose sum is σ = 281249280. Its totient is φ = 93199680.

The previous prime is 165939929. The next prime is 165939971. The reversal of 165939939 is 939939561.

It is a happy number.

165939939 is a `hidden beast` number, since 16 + 593 + 9 + 9 + 39 = 666.

It is not a de Polignac number, because 165939939 - 2⁴ = 165939923 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165939929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 87469 + ... + 89345.

It is an arithmetic number, because the mean of its divisors is an integer number (5859360).

Almost surely, 2^165939939 is an apocalyptic number.

165939939 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

165939939 is a deficient number, since it is larger than the sum of its proper divisors (115309341).

165939939 is a wasteful number, since it uses less digits than its factorization.

165939939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1960 (or 1957 counting only the distinct ones).

The product of its digits is 1771470, while the sum is 54.

The square root of 165939939 is about 12881.7676970205. The cubic root of 165939939 is about 549.5201754582.

The spelling of 165939939 in words is "one hundred sixty-five million, nine hundred thirty-nine thousand, nine hundred thirty-nine".