664389409 has 2 divisors, whose sum is σ = 664389410. Its totient is φ = 664389408.

The previous prime is 664389347. The next prime is 664389457. The reversal of 664389409 is 904983466.

664389409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 603783184 + 60606225 = 24572^2 + 7785^2 .

It is a cyclic number.

It is not a de Polignac number, because 664389409 - 2⁹ = 664388897 is a prime.

It is not a weakly prime, because it can be changed into another prime (664389469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332194704 + 332194705.

It is an arithmetic number, because the mean of its divisors is an integer number (332194705).

Almost surely, 2^664389409 is an apocalyptic number.

It is an amenable number.

664389409 is a deficient number, since it is larger than the sum of its proper divisors (1).

664389409 is an equidigital number, since it uses as much as digits as its factorization.

664389409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1119744, while the sum is 49.

The square root of 664389409 is about 25775.7523459549. The cubic root of 664389409 is about 872.5846461009.

The spelling of 664389409 in words is "six hundred sixty-four million, three hundred eighty-nine thousand, four hundred nine".