649668791 has 2 divisors, whose sum is σ = 649668792. Its totient is φ = 649668790.

The previous prime is 649668769. The next prime is 649668839. The reversal of 649668791 is 197866946.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 649668791 - 2¹⁴ = 649652407 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649668731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324834395 + 324834396.

It is an arithmetic number, because the mean of its divisors is an integer number (324834396).

Almost surely, 2^649668791 is an apocalyptic number.

649668791 is a deficient number, since it is larger than the sum of its proper divisors (1).

649668791 is an equidigital number, since it uses as much as digits as its factorization.

649668791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3919104, while the sum is 56.

The square root of 649668791 is about 25488.6011973980. The cubic root of 649668791 is about 866.0919489651.

The spelling of 649668791 in words is "six hundred forty-nine million, six hundred sixty-eight thousand, seven hundred ninety-one".