204965 has 4 divisors (see below), whose sum is σ = 245964. Its totient is φ = 163968.

The previous prime is 204947. The next prime is 204973. The reversal of 204965 is 569402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 569402 = 2 ⋅284701.

It can be written as a sum of positive squares in 2 ways, for example, as 49729 + 155236 = 223^2 + 394^2 .

It is a cyclic number.

It is not a de Polignac number, because 204965 - 2¹² = 200869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20492 + ... + 20501.

It is an arithmetic number, because the mean of its divisors is an integer number (61491).

2²⁰⁴⁹⁶⁵ is an apocalyptic number.

It is an amenable number.

204965 is a deficient number, since it is larger than the sum of its proper divisors (40999).

204965 is an equidigital number, since it uses as much as digits as its factorization.

204965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40998.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 204965 is about 452.7306042229. The cubic root of 204965 is about 58.9603295518.

The spelling of 204965 in words is "two hundred four thousand, nine hundred sixty-five".