165855907 has 4 divisors (see below), whose sum is σ = 189549616. Its totient is φ = 142162200.

The previous prime is 165855871. The next prime is 165855913. The reversal of 165855907 is 709558561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 709558561 = 229 ⋅3098509.

It is a cyclic number.

It is not a de Polignac number, because 165855907 - 2⁷ = 165855779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165855307) 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 3 ways as a sum of consecutive naturals, for example, 11846844 + ... + 11846857.

It is an arithmetic number, because the mean of its divisors is an integer number (47387404).

Almost surely, 2^165855907 is an apocalyptic number.

165855907 is a deficient number, since it is larger than the sum of its proper divisors (23693709).

165855907 is an equidigital number, since it uses as much as digits as its factorization.

165855907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23693708.

The product of its (nonzero) digits is 378000, while the sum is 46.

The square root of 165855907 is about 12878.5056198303. The cubic root of 165855907 is about 549.4274007740.

The spelling of 165855907 in words is "one hundred sixty-five million, eight hundred fifty-five thousand, nine hundred seven".