204005509 has 2 divisors, whose sum is σ = 204005510. Its totient is φ = 204005508.

The previous prime is 204005479. The next prime is 204005551. The reversal of 204005509 is 905500402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152596609 + 51408900 = 12353^2 + 7170^2 .

It is a cyclic number.

It is not a de Polignac number, because 204005509 - 2¹⁹ = 203481221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204005209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102002754 + 102002755.

It is an arithmetic number, because the mean of its divisors is an integer number (102002755).

Almost surely, 2^204005509 is an apocalyptic number.

It is an amenable number.

204005509 is a deficient number, since it is larger than the sum of its proper divisors (1).

204005509 is an equidigital number, since it uses as much as digits as its factorization.

204005509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 204005509 is about 14283.0497093583. The cubic root of 204005509 is about 588.6818306913.

The spelling of 204005509 in words is "two hundred four million, five thousand, five hundred nine".