204209 has 4 divisors (see below), whose sum is σ = 208116. Its totient is φ = 200304.

The previous prime is 204173. The next prime is 204233. The reversal of 204209 is 902402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 902402 = 2 ⋅451201.

It can be written as a sum of positive squares in 2 ways, for example, as 183184 + 21025 = 428^2 + 145^2 .

It is a cyclic number.

It is not a de Polignac number, because 204209 - 2⁸ = 203953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204299) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1874 + ... + 1979.

It is an arithmetic number, because the mean of its divisors is an integer number (52029).

2²⁰⁴²⁰⁹ is an apocalyptic number.

It is an amenable number.

204209 is a deficient number, since it is larger than the sum of its proper divisors (3907).

204209 is an equidigital number, since it uses as much as digits as its factorization.

204209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3906.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 204209 is about 451.8948992852. The cubic root of 204209 is about 58.8877498033.

The spelling of 204209 in words is "two hundred four thousand, two hundred nine".