165623 has 8 divisors (see below), whose sum is σ = 182400. Its totient is φ = 149688.

The previous prime is 165617. The next prime is 165653. The reversal of 165623 is 326561.

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

It is a cyclic number.

It is not a de Polignac number, because 165623 - 2⁶ = 165559 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165653) 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 7 ways as a sum of consecutive naturals, for example, 248 + ... + 626.

It is an arithmetic number, because the mean of its divisors is an integer number (22800).

2¹⁶⁵⁶²³ is an apocalyptic number.

165623 is a deficient number, since it is larger than the sum of its proper divisors (16777).

165623 is a wasteful number, since it uses less digits than its factorization.

165623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421.

The product of its digits is 1080, while the sum is 23.

The square root of 165623 is about 406.9680577146. The cubic root of 165623 is about 54.9170098243.

Subtracting from 165623 its sum of digits (23), we obtain a triangular number (165600 = T₅₇₅).

The spelling of 165623 in words is "one hundred sixty-five thousand, six hundred twenty-three".