678808909 has 2 divisors, whose sum is σ = 678808910. Its totient is φ = 678808908.

The previous prime is 678808859. The next prime is 678808927. The reversal of 678808909 is 909808876.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 374306409 + 304502500 = 19347^2 + 17450^2 .

It is a cyclic number.

It is not a de Polignac number, because 678808909 - 2⁹ = 678808397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 678808909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678808939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339404454 + 339404455.

It is an arithmetic number, because the mean of its divisors is an integer number (339404455).

Almost surely, 2^678808909 is an apocalyptic number.

It is an amenable number.

678808909 is a deficient number, since it is larger than the sum of its proper divisors (1).

678808909 is an equidigital number, since it uses as much as digits as its factorization.

678808909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1741824, while the sum is 55.

The square root of 678808909 is about 26053.9614838128. The cubic root of 678808909 is about 878.8522006119.

The spelling of 678808909 in words is "six hundred seventy-eight million, eight hundred eight thousand, nine hundred nine".