636942816647 has 2 divisors, whose sum is σ = 636942816648. Its totient is φ = 636942816646.

The previous prime is 636942816617. The next prime is 636942816701. The reversal of 636942816647 is 746618249636.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-636942816647 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 636942816647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636942816607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318471408323 + 318471408324.

It is an arithmetic number, because the mean of its divisors is an integer number (318471408324).

Almost surely, 2^636942816647 is an apocalyptic number.

636942816647 is a deficient number, since it is larger than the sum of its proper divisors (1).

636942816647 is an equidigital number, since it uses as much as digits as its factorization.

636942816647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62705664, while the sum is 62.

The spelling of 636942816647 in words is "six hundred thirty-six billion, nine hundred forty-two million, eight hundred sixteen thousand, six hundred forty-seven".