204404209 has 15 divisors (see below), whose sum is σ = 224890087. Its totient is φ = 185746624.

The previous prime is 204404191. The next prime is 204404219. The reversal of 204404209 is 902404402.

The square root of 204404209 is 14297.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 7 ways, for example, as 37271025 + 167133184 = 6105^2 + 12928^2 .

It is not a de Polignac number, because 204404209 - 2⁹ = 204403697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204404219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 7048407 + ... + 7048435.

Almost surely, 2^204404209 is an apocalyptic number.

204404209 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

204404209 is the 14297-th square number.

204404209 is the 7149-th centered octagonal number.

It is an amenable number.

204404209 is a deficient number, since it is larger than the sum of its proper divisors (20485878).

204404209 is an frugal number, since it uses more digits than its factorization.

204404209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The cubic root of 204404209 is about 589.0650796731.

Multiplying 204404209 by its sum of digits (25), we get a square (5110105225 = 71485²).

Multiplying 204404209 by its product of nonzero digits (2304), we get a square (470947297536 = 686256²).

It can be divided in two parts, 20440 and 4209, that added together give a square (24649 = 157²).

The spelling of 204404209 in words is "two hundred four million, four hundred four thousand, two hundred nine".