664062809 has 2 divisors, whose sum is σ = 664062810. Its totient is φ = 664062808.

The previous prime is 664062767. The next prime is 664062821. The reversal of 664062809 is 908260466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 347934409 + 316128400 = 18653^2 + 17780^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664062809 is a prime.

It is not a weakly prime, because it can be changed into another prime (664062829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332031404 + 332031405.

It is an arithmetic number, because the mean of its divisors is an integer number (332031405).

Almost surely, 2^664062809 is an apocalyptic number.

It is an amenable number.

664062809 is a deficient number, since it is larger than the sum of its proper divisors (1).

664062809 is an equidigital number, since it uses as much as digits as its factorization.

664062809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 664062809 is about 25769.4161555903. The cubic root of 664062809 is about 872.4416411844.

The spelling of 664062809 in words is "six hundred sixty-four million, sixty-two thousand, eight hundred nine".