204809 has 8 divisors (see below), whose sum is σ = 229152. Its totient is φ = 181440.

The previous prime is 204803. The next prime is 204821. The reversal of 204809 is 908402.

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 204809 - 2⁴ = 204793 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 204809.

It is not an unprimeable number, because it can be changed into a prime (204803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 257 + ... + 689.

It is an arithmetic number, because the mean of its divisors is an integer number (28644).

2²⁰⁴⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

204809 is a deficient number, since it is larger than the sum of its proper divisors (24343).

204809 is a wasteful number, since it uses less digits than its factorization.

204809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 487.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 204809 is about 452.5582835393. The cubic root of 204809 is about 58.9453674105.

The spelling of 204809 in words is "two hundred four thousand, eight hundred nine".