646566665579 has 2 divisors, whose sum is σ = 646566665580. Its totient is φ = 646566665578.

The previous prime is 646566665551. The next prime is 646566665683. The reversal of 646566665579 is 975566665646.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646566665579 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (646566661579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323283332789 + 323283332790.

It is an arithmetic number, because the mean of its divisors is an integer number (323283332790).

Almost surely, 2^646566665579 is an apocalyptic number.

646566665579 is a deficient number, since it is larger than the sum of its proper divisors (1).

646566665579 is an equidigital number, since it uses as much as digits as its factorization.

646566665579 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1469664000, while the sum is 71.

The spelling of 646566665579 in words is "six hundred forty-six billion, five hundred sixty-six million, six hundred sixty-five thousand, five hundred seventy-nine".