165813 has 8 divisors (see below), whose sum is σ = 232800. Its totient is φ = 104688.

The previous prime is 165811. The next prime is 165817. The reversal of 165813 is 318561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 165813 - 2¹ = 165811 is a prime.

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 165813.

It is not an unprimeable number, because it can be changed into a prime (165811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1398 + ... + 1511.

It is an arithmetic number, because the mean of its divisors is an integer number (29100).

2¹⁶⁵⁸¹³ is an apocalyptic number.

It is an amenable number.

165813 is a deficient number, since it is larger than the sum of its proper divisors (66987).

165813 is a wasteful number, since it uses less digits than its factorization.

165813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2931.

The product of its digits is 720, while the sum is 24.

The square root of 165813 is about 407.2014243590. The cubic root of 165813 is about 54.9380017647.

The spelling of 165813 in words is "one hundred sixty-five thousand, eight hundred thirteen".