204909 has 8 divisors (see below), whose sum is σ = 275520. Its totient is φ = 135456.

The previous prime is 204887. The next prime is 204913. The reversal of 204909 is 909402.

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

It is not a de Polignac number, because 204909 - 2⁷ = 204781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204979) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 297 + ... + 705.

It is an arithmetic number, because the mean of its divisors is an integer number (34440).

2²⁰⁴⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

204909 is a deficient number, since it is larger than the sum of its proper divisors (70611).

204909 is a wasteful number, since it uses less digits than its factorization.

204909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 204909 is about 452.6687530634. The cubic root of 204909 is about 58.9549594005.

The spelling of 204909 in words is "two hundred four thousand, nine hundred nine".