663206689 has 2 divisors, whose sum is σ = 663206690. Its totient is φ = 663206688.

The previous prime is 663206581. The next prime is 663206699. The reversal of 663206689 is 986602366.

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., 442387089 + 220819600 = 21033^2 + 14860^2 .

It is a cyclic number.

It is not a de Polignac number, because 663206689 - 2⁷ = 663206561 is a prime.

It is a super-2 number, since 2×663206689² = 879686224668685442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (663206699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331603344 + 331603345.

It is an arithmetic number, because the mean of its divisors is an integer number (331603345).

Almost surely, 2^663206689 is an apocalyptic number.

It is an amenable number.

663206689 is a deficient number, since it is larger than the sum of its proper divisors (1).

663206689 is an equidigital number, since it uses as much as digits as its factorization.

663206689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 559872, while the sum is 46.

The square root of 663206689 is about 25752.7996342145. The cubic root of 663206689 is about 872.0665582174.

The spelling of 663206689 in words is "six hundred sixty-three million, two hundred six thousand, six hundred eighty-nine".