689407709 has 2 divisors, whose sum is σ = 689407710. Its totient is φ = 689407708.

The previous prime is 689407639. The next prime is 689407739. The reversal of 689407709 is 907704986.

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., 475370809 + 214036900 = 21803^2 + 14630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-689407709 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 (689407739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344703854 + 344703855.

It is an arithmetic number, because the mean of its divisors is an integer number (344703855).

Almost surely, 2^689407709 is an apocalyptic number.

It is an amenable number.

689407709 is a deficient number, since it is larger than the sum of its proper divisors (1).

689407709 is an equidigital number, since it uses as much as digits as its factorization.

689407709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 762048, while the sum is 50.

The square root of 689407709 is about 26256.5745861870. The cubic root of 689407709 is about 883.4026786745.

The spelling of 689407709 in words is "six hundred eighty-nine million, four hundred seven thousand, seven hundred nine".