165811 has 2 divisors, whose sum is σ = 165812. Its totient is φ = 165810.

The previous prime is 165799. The next prime is 165817. The reversal of 165811 is 118561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165811 - 2⁵ = 165779 is a prime.

It is not a weakly prime, because it can be changed into another prime (165817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82905 + 82906.

It is an arithmetic number, because the mean of its divisors is an integer number (82906).

2¹⁶⁵⁸¹¹ is an apocalyptic number.

165811 is a deficient number, since it is larger than the sum of its proper divisors (1).

165811 is an equidigital number, since it uses as much as digits as its factorization.

165811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 22.

The square root of 165811 is about 407.1989685645. The cubic root of 165811 is about 54.9377808804.

The spelling of 165811 in words is "one hundred sixty-five thousand, eight hundred eleven".