204559 has 4 divisors (see below), whose sum is σ = 205504. Its totient is φ = 203616.

The previous prime is 204557. The next prime is 204563. The reversal of 204559 is 955402.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 204559 - 2¹ = 204557 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34 + ... + 640.

It is an arithmetic number, because the mean of its divisors is an integer number (51376).

2²⁰⁴⁵⁵⁹ is an apocalyptic number.

204559 is a deficient number, since it is larger than the sum of its proper divisors (945).

204559 is an equidigital number, since it uses as much as digits as its factorization.

204559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 944.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 204559 is about 452.2819916822. The cubic root of 204559 is about 58.9213737678.

The spelling of 204559 in words is "two hundred four thousand, five hundred fifty-nine".