646764193 has 2 divisors, whose sum is σ = 646764194. Its totient is φ = 646764192.

The previous prime is 646764187. The next prime is 646764317. The reversal of 646764193 is 391467646.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 370639504 + 276124689 = 19252^2 + 16617^2 .

It is a cyclic number.

It is not a de Polignac number, because 646764193 - 2²⁹ = 109893281 is a prime.

It is not a weakly prime, because it can be changed into another prime (646764103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323382096 + 323382097.

It is an arithmetic number, because the mean of its divisors is an integer number (323382097).

Almost surely, 2^646764193 is an apocalyptic number.

It is an amenable number.

646764193 is a deficient number, since it is larger than the sum of its proper divisors (1).

646764193 is an equidigital number, since it uses as much as digits as its factorization.

646764193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 46.

The square root of 646764193 is about 25431.5589966482. The cubic root of 646764193 is about 864.7992865186.

The spelling of 646764193 in words is "six hundred forty-six million, seven hundred sixty-four thousand, one hundred ninety-three".