664405601 has 2 divisors, whose sum is σ = 664405602. Its totient is φ = 664405600.

The previous prime is 664405579. The next prime is 664405649. The reversal of 664405601 is 106504466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 492795601 + 171610000 = 22199^2 + 13100^2 .

It is a cyclic number.

It is not a de Polignac number, because 664405601 - 2⁶ = 664405537 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (664405681) 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, 332202800 + 332202801.

It is an arithmetic number, because the mean of its divisors is an integer number (332202801).

Almost surely, 2^664405601 is an apocalyptic number.

It is an amenable number.

664405601 is a deficient number, since it is larger than the sum of its proper divisors (1).

664405601 is an equidigital number, since it uses as much as digits as its factorization.

664405601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 664405601 is about 25776.0664376859. The cubic root of 664405601 is about 872.5917347027.

The spelling of 664405601 in words is "six hundred sixty-four million, four hundred five thousand, six hundred one".