165645923 has 4 divisors (see below), whose sum is σ = 165673200. Its totient is φ = 165618648.

The previous prime is 165645919. The next prime is 165645967. The reversal of 165645923 is 329546561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 329546561 = 41 ⋅8037721.

It is a cyclic number.

It is not a de Polignac number, because 165645923 - 2² = 165645919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165645913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53 + ... + 18201.

It is an arithmetic number, because the mean of its divisors is an integer number (41418300).

Almost surely, 2^165645923 is an apocalyptic number.

165645923 is a deficient number, since it is larger than the sum of its proper divisors (27277).

165645923 is an equidigital number, since it uses as much as digits as its factorization.

165645923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27276.

The product of its digits is 194400, while the sum is 41.

The square root of 165645923 is about 12870.3505391267. The cubic root of 165645923 is about 549.1954329801.

The spelling of 165645923 in words is "one hundred sixty-five million, six hundred forty-five thousand, nine hundred twenty-three".