206563664689 has 2 divisors, whose sum is σ = 206563664690. Its totient is φ = 206563664688.

The previous prime is 206563664641. The next prime is 206563664731. The reversal of 206563664689 is 986466365602.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 192728024064 + 13835640625 = 439008^2 + 117625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206563664689 is a prime.

It is not a weakly prime, because it can be changed into another prime (206563664189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103281832344 + 103281832345.

It is an arithmetic number, because the mean of its divisors is an integer number (103281832345).

Almost surely, 2^206563664689 is an apocalyptic number.

It is an amenable number.

206563664689 is a deficient number, since it is larger than the sum of its proper divisors (1).

206563664689 is an equidigital number, since it uses as much as digits as its factorization.

206563664689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 67184640, while the sum is 61.

The spelling of 206563664689 in words is "two hundred six billion, five hundred sixty-three million, six hundred sixty-four thousand, six hundred eighty-nine".