165091 has 4 divisors (see below), whose sum is σ = 173800. Its totient is φ = 156384.

The previous prime is 165089. The next prime is 165103. The reversal of 165091 is 190561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165091 - 2¹ = 165089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4326 + ... + 4363.

It is an arithmetic number, because the mean of its divisors is an integer number (43450).

2¹⁶⁵⁰⁹¹ is an apocalyptic number.

165091 is a deficient number, since it is larger than the sum of its proper divisors (8709).

165091 is an equidigital number, since it uses as much as digits as its factorization.

165091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8708.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 165091 is about 406.3139180486. The cubic root of 165091 is about 54.8581468509.

The spelling of 165091 in words is "one hundred sixty-five thousand, ninety-one".