165615 has 16 divisors (see below), whose sum is σ = 270816. Its totient is φ = 86400.

The previous prime is 165611. The next prime is 165617. The reversal of 165615 is 516561.

It is not a de Polignac number, because 165615 - 2² = 165611 is a prime.

It is an Ulam number.

165615 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 825 + ... + 1005.

It is an arithmetic number, because the mean of its divisors is an integer number (16926).

2¹⁶⁵⁶¹⁵ is an apocalyptic number.

165615 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

165615 is a deficient number, since it is larger than the sum of its proper divisors (105201).

165615 is a wasteful number, since it uses less digits than its factorization.

165615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250.

The product of its digits is 900, while the sum is 24.

The square root of 165615 is about 406.9582288147. The cubic root of 165615 is about 54.9161256010.

It can be divided in two parts, 165 and 615, that multiplied together give a triangular number (101475 = T₄₅₀).

The spelling of 165615 in words is "one hundred sixty-five thousand, six hundred fifteen".