680656789 has 2 divisors, whose sum is σ = 680656790. Its totient is φ = 680656788.

The previous prime is 680656759. The next prime is 680656799. The reversal of 680656789 is 987656086.

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., 648109764 + 32547025 = 25458^2 + 5705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-680656789 is a 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 (680656759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340328394 + 340328395.

It is an arithmetic number, because the mean of its divisors is an integer number (340328395).

Almost surely, 2^680656789 is an apocalyptic number.

It is an amenable number.

680656789 is a deficient number, since it is larger than the sum of its proper divisors (1).

680656789 is an equidigital number, since it uses as much as digits as its factorization.

680656789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4354560, while the sum is 55.

The square root of 680656789 is about 26089.3999356060. The cubic root of 680656789 is about 879.6489599339.

The spelling of 680656789 in words is "six hundred eighty million, six hundred fifty-six thousand, seven hundred eighty-nine".