204889409 has 2 divisors, whose sum is σ = 204889410. Its totient is φ = 204889408.

The previous prime is 204889397. The next prime is 204889411. The reversal of 204889409 is 904988402.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 204575809 + 313600 = 14303^2 + 560^2 .

It is a cyclic number.

It is not a de Polignac number, because 204889409 - 2⁴ = 204889393 is a prime.

Together with 204889411, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 204889409.

It is not a weakly prime, because it can be changed into another prime (204889429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102444704 + 102444705.

It is an arithmetic number, because the mean of its divisors is an integer number (102444705).

Almost surely, 2^204889409 is an apocalyptic number.

It is an amenable number.

204889409 is a deficient number, since it is larger than the sum of its proper divisors (1).

204889409 is an equidigital number, since it uses as much as digits as its factorization.

204889409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 165888, while the sum is 44.

The square root of 204889409 is about 14313.9585370365. The cubic root of 204889409 is about 589.5308047957.

The spelling of 204889409 in words is "two hundred four million, eight hundred eighty-nine thousand, four hundred nine".