165823 has 4 divisors (see below), whose sum is σ = 189520. Its totient is φ = 142128.

The previous prime is 165817. The next prime is 165829. The reversal of 165823 is 328561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 328561 = 79 ⋅4159.

It is an interprime number because it is at equal distance from previous prime (165817) and next prime (165829).

It is not a de Polignac number, because 165823 - 2⁹ = 165311 is a prime.

It is a d-powerful number, because it can be written as 1 + 6⁶ + 8⁵ + 5⁷ + 2¹³ + 3⁴ .

It is a Duffinian number.

165823 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165829) 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, 11838 + ... + 11851.

It is an arithmetic number, because the mean of its divisors is an integer number (47380).

2¹⁶⁵⁸²³ is an apocalyptic number.

165823 is a deficient number, since it is larger than the sum of its proper divisors (23697).

165823 is an equidigital number, since it uses as much as digits as its factorization.

165823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23696.

The product of its digits is 1440, while the sum is 25.

The square root of 165823 is about 407.2137031093. The cubic root of 165823 is about 54.9391061593.

It can be divided in two parts, 1658 and 23, that added together give a square (1681 = 41²).

The spelling of 165823 in words is "one hundred sixty-five thousand, eight hundred twenty-three".