204905 has 8 divisors (see below), whose sum is σ = 248832. Its totient is φ = 161968.

The previous prime is 204887. The next prime is 204913. The reversal of 204905 is 509402.

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 204905 - 2¹⁶ = 139369 is a prime.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 344 + ... + 726.

It is an arithmetic number, because the mean of its divisors is an integer number (31104).

2²⁰⁴⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

204905 is a deficient number, since it is larger than the sum of its proper divisors (43927).

204905 is a wasteful number, since it uses less digits than its factorization.

204905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 204905 is about 452.6643348001. The cubic root of 204905 is about 58.9545757808.

The spelling of 204905 in words is "two hundred four thousand, nine hundred five".