646212817 has 2 divisors, whose sum is σ = 646212818. Its totient is φ = 646212816.

The previous prime is 646212799. The next prime is 646212859. The reversal of 646212817 is 718212646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 614841616 + 31371201 = 24796^2 + 5601^2 .

It is a cyclic number.

It is not a de Polignac number, because 646212817 - 2⁷ = 646212689 is a prime.

It is not a weakly prime, because it can be changed into another prime (646212877) 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, 323106408 + 323106409.

It is an arithmetic number, because the mean of its divisors is an integer number (323106409).

Almost surely, 2^646212817 is an apocalyptic number.

It is an amenable number.

646212817 is a deficient number, since it is larger than the sum of its proper divisors (1).

646212817 is an equidigital number, since it uses as much as digits as its factorization.

646212817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 37.

The square root of 646212817 is about 25420.7162959662. The cubic root of 646212817 is about 864.5534652738.

The spelling of 646212817 in words is "six hundred forty-six million, two hundred twelve thousand, eight hundred seventeen".