649683436921 has 2 divisors, whose sum is σ = 649683436922. Its totient is φ = 649683436920.

The previous prime is 649683436907. The next prime is 649683437017. The reversal of 649683436921 is 129634386946.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 540172081296 + 109511355625 = 734964^2 + 330925^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649683436921 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 649683436921.

It is not a weakly prime, because it can be changed into another prime (649683436021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324841718460 + 324841718461.

It is an arithmetic number, because the mean of its divisors is an integer number (324841718461).

Almost surely, 2^649683436921 is an apocalyptic number.

It is an amenable number.

649683436921 is a deficient number, since it is larger than the sum of its proper divisors (1).

649683436921 is an equidigital number, since it uses as much as digits as its factorization.

649683436921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40310784, while the sum is 61.

The spelling of 649683436921 in words is "six hundred forty-nine billion, six hundred eighty-three million, four hundred thirty-six thousand, nine hundred twenty-one".