204865609 has 8 divisors (see below), whose sum is σ = 222650120. Its totient is φ = 187370496.

The previous prime is 204865603. The next prime is 204865627. The reversal of 204865609 is 906568402.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4020025 + 200845584 = 2005^2 + 14172^2 .

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 204865609 - 2⁷ = 204865481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204865603) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70872 + ... + 73705.

It is an arithmetic number, because the mean of its divisors is an integer number (27831265).

Almost surely, 2^204865609 is an apocalyptic number.

It is an amenable number.

204865609 is a deficient number, since it is larger than the sum of its proper divisors (17784511).

204865609 is a wasteful number, since it uses less digits than its factorization.

204865609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144699.

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 204865609 is about 14313.1271565651. The cubic root of 204865609 is about 589.5079772347.

The spelling of 204865609 in words is "two hundred four million, eight hundred sixty-five thousand, six hundred nine".