680993909 has 2 divisors, whose sum is σ = 680993910. Its totient is φ = 680993908.

The previous prime is 680993897. The next prime is 680993947. The reversal of 680993909 is 909399086.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 680688100 + 305809 = 26090^2 + 553^2 .

It is a cyclic number.

It is not a de Polignac number, because 680993909 - 2²⁸ = 412558453 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 (680992909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340496954 + 340496955.

It is an arithmetic number, because the mean of its divisors is an integer number (340496955).

Almost surely, 2^680993909 is an apocalyptic number.

It is an amenable number.

680993909 is a deficient number, since it is larger than the sum of its proper divisors (1).

680993909 is an equidigital number, since it uses as much as digits as its factorization.

680993909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 944784, while the sum is 53.

The square root of 680993909 is about 26095.8599973252. The cubic root of 680993909 is about 879.7941619980.

The spelling of 680993909 in words is "six hundred eighty million, nine hundred ninety-three thousand, nine hundred nine".