687959309 has 2 divisors, whose sum is σ = 687959310. Its totient is φ = 687959308.

The previous prime is 687959299. The next prime is 687959317. The reversal of 687959309 is 903959786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 687593284 + 366025 = 26222^2 + 605^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687959309 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687959359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343979654 + 343979655.

It is an arithmetic number, because the mean of its divisors is an integer number (343979655).

Almost surely, 2^687959309 is an apocalyptic number.

It is an amenable number.

687959309 is a deficient number, since it is larger than the sum of its proper divisors (1).

687959309 is an equidigital number, since it uses as much as digits as its factorization.

687959309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3674160, while the sum is 56.

The square root of 687959309 is about 26228.9784208230. The cubic root of 687959309 is about 882.7835880488.

The spelling of 687959309 in words is "six hundred eighty-seven million, nine hundred fifty-nine thousand, three hundred nine".