646405659389977 has 2 divisors, whose sum is σ = 646405659389978. Its totient is φ = 646405659389976.

The previous prime is 646405659389951. The next prime is 646405659390017. The reversal of 646405659389977 is 779983956504646.

646405659389977 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 506888481185856 + 139517178204121 = 22514184^2 + 11811739^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646405659389977 is a prime.

It is not a weakly prime, because it can be changed into another prime (646405659389947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323202829694988 + 323202829694989.

It is an arithmetic number, because the mean of its divisors is an integer number (323202829694989).

Almost surely, 2^{646405659389977} is an apocalyptic number.

It is an amenable number.

646405659389977 is a deficient number, since it is larger than the sum of its proper divisors (1).

646405659389977 is an equidigital number, since it uses as much as digits as its factorization.

646405659389977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 74071065600, while the sum is 88.

The spelling of 646405659389977 in words is "six hundred forty-six trillion, four hundred five billion, six hundred fifty-nine million, three hundred eighty-nine thousand, nine hundred seventy-seven".