204409 has 4 divisors (see below), whose sum is σ = 207360. Its totient is φ = 201460.

The previous prime is 204397. The next prime is 204427. The reversal of 204409 is 904402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 904402 = 2 ⋅452201.

It is a cyclic number.

It is not a de Polignac number, because 204409 - 2⁵ = 204377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204439) 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, 1369 + ... + 1510.

It is an arithmetic number, because the mean of its divisors is an integer number (51840).

2²⁰⁴⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

204409 is a deficient number, since it is larger than the sum of its proper divisors (2951).

204409 is an equidigital number, since it uses as much as digits as its factorization.

204409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2950.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 204409 is about 452.1161355227. The cubic root of 204409 is about 58.9069681974.

It can be divided in two parts, 20440 and 9, that added together give a square (20449 = 143²).

The spelling of 204409 in words is "two hundred four thousand, four hundred nine".