165855903 has 16 divisors (see below), whose sum is σ = 229685760. Its totient is φ = 106378496.

The previous prime is 165855871. The next prime is 165855913. The reversal of 165855903 is 309558561.

It is a cyclic number.

It is not a de Polignac number, because 165855903 - 2⁵ = 165855871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165855913) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1650 + ... + 18287.

It is an arithmetic number, because the mean of its divisors is an integer number (14355360).

Almost surely, 2^165855903 is an apocalyptic number.

165855903 is a deficient number, since it is larger than the sum of its proper divisors (63829857).

165855903 is a wasteful number, since it uses less digits than its factorization.

165855903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20046.

The product of its (nonzero) digits is 162000, while the sum is 42.

The square root of 165855903 is about 12878.5054645328. The cubic root of 165855903 is about 549.4273963571.

The spelling of 165855903 in words is "one hundred sixty-five million, eight hundred fifty-five thousand, nine hundred three".