646839659 has 2 divisors, whose sum is σ = 646839660. Its totient is φ = 646839658.

The previous prime is 646839631. The next prime is 646839733. The reversal of 646839659 is 956938646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646839659 - 2²⁸ = 378404203 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (646839619) 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, 323419829 + 323419830.

It is an arithmetic number, because the mean of its divisors is an integer number (323419830).

Almost surely, 2^646839659 is an apocalyptic number.

646839659 is a deficient number, since it is larger than the sum of its proper divisors (1).

646839659 is an equidigital number, since it uses as much as digits as its factorization.

646839659 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8398080, while the sum is 56.

The square root of 646839659 is about 25433.0426610738. The cubic root of 646839659 is about 864.8329208300.

The spelling of 646839659 in words is "six hundred forty-six million, eight hundred thirty-nine thousand, six hundred fifty-nine".