165911 has 4 divisors (see below), whose sum is σ = 166824. Its totient is φ = 165000.

The previous prime is 165901. The next prime is 165931. The reversal of 165911 is 119561.

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 a de Polignac number, because none of the positive numbers 2^k-165911 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80 + ... + 581.

It is an arithmetic number, because the mean of its divisors is an integer number (41706).

2¹⁶⁵⁹¹¹ is an apocalyptic number.

165911 is a deficient number, since it is larger than the sum of its proper divisors (913).

165911 is an equidigital number, since it uses as much as digits as its factorization.

165911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 912.

The product of its digits is 270, while the sum is 23.

The square root of 165911 is about 407.3217401514. The cubic root of 165911 is about 54.9488229183.

The spelling of 165911 in words is "one hundred sixty-five thousand, nine hundred eleven".