165791 has 4 divisors (see below), whose sum is σ = 166632. Its totient is φ = 164952.

The previous prime is 165779. The next prime is 165799. The reversal of 165791 is 197561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 165791 - 2¹⁰ = 164767 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 165791.

It is not an unprimeable number, because it can be changed into a prime (165799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56 + ... + 578.

It is an arithmetic number, because the mean of its divisors is an integer number (41658).

2¹⁶⁵⁷⁹¹ is an apocalyptic number.

165791 is a deficient number, since it is larger than the sum of its proper divisors (841).

165791 is an equidigital number, since it uses as much as digits as its factorization.

165791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840.

The product of its digits is 1890, while the sum is 29.

The square root of 165791 is about 407.1744098049. The cubic root of 165791 is about 54.9355719401.

The spelling of 165791 in words is "one hundred sixty-five thousand, seven hundred ninety-one".