204401909 has 2 divisors, whose sum is σ = 204401910. Its totient is φ = 204401908.

The previous prime is 204401893. The next prime is 204401921. The reversal of 204401909 is 909104402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105001009 + 99400900 = 10247^2 + 9970^2 .

It is a cyclic number.

It is not a de Polignac number, because 204401909 - 2⁴ = 204401893 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204401969) 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 as a sum of consecutive naturals, namely, 102200954 + 102200955.

It is an arithmetic number, because the mean of its divisors is an integer number (102200955).

Almost surely, 2^204401909 is an apocalyptic number.

It is an amenable number.

204401909 is a deficient number, since it is larger than the sum of its proper divisors (1).

204401909 is an equidigital number, since it uses as much as digits as its factorization.

204401909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 204401909 is about 14296.9195633185. The cubic root of 204401909 is about 589.0628702360.

The spelling of 204401909 in words is "two hundred four million, four hundred one thousand, nine hundred nine".