204985665 has 12 divisors (see below), whose sum is σ = 355308564. Its totient is φ = 109325664.

The previous prime is 204985639. The next prime is 204985667. The reversal of 204985665 is 566589402.

204985665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 122412096 + 82573569 = 11064^2 + 9087^2 .

It is not a de Polignac number, because 204985665 - 2⁵ = 204985633 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 4555237 = 204985665 / (2 + 0 + 4 + 9 + 8 + 5 + 6 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 204985665.

It is not an unprimeable number, because it can be changed into a prime (204985667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2277574 + ... + 2277663.

It is an arithmetic number, because the mean of its divisors is an integer number (29609047).

Almost surely, 2^204985665 is an apocalyptic number.

It is an amenable number.

204985665 is a deficient number, since it is larger than the sum of its proper divisors (150322899).

204985665 is a wasteful number, since it uses less digits than its factorization.

204985665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4555248 (or 4555245 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The square root of 204985665 is about 14317.3204546102. The cubic root of 204985665 is about 589.6231098648.

The spelling of 204985665 in words is "two hundred four million, nine hundred eighty-five thousand, six hundred sixty-five".