165818 has 8 divisors (see below), whose sum is σ = 263412. Its totient is φ = 78016.

The previous prime is 165817. The next prime is 165829. The reversal of 165818 is 818561.

165818 = 112² + 113² + ... + 123².

It can be written as a sum of positive squares in 2 ways, for example, as 165649 + 169 = 407^2 + 13^2 .

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

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 165818.

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 3 ways as a sum of consecutive naturals, for example, 2405 + ... + 2472.

2¹⁶⁵⁸¹⁸ is an apocalyptic number.

165818 is a deficient number, since it is larger than the sum of its proper divisors (97594).

165818 is a wasteful number, since it uses less digits than its factorization.

165818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4896.

The product of its digits is 1920, while the sum is 29.

The square root of 165818 is about 407.2075637804. The cubic root of 165818 is about 54.9385539676.

The spelling of 165818 in words is "one hundred sixty-five thousand, eight hundred eighteen".