6688909 has 2 divisors, whose sum is σ = 6688910. Its totient is φ = 6688908.

The previous prime is 6688907. The next prime is 6688919. The reversal of 6688909 is 9098866.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5076009 + 1612900 = 2253^2 + 1270^2 .

It is a cyclic number.

It is not a de Polignac number, because 6688909 - 2¹ = 6688907 is a prime.

It is a super-2 number, since 2×6688909² = 89483007220562, which contains 22 as substring.

Together with 6688907, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6688907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3344454 + 3344455.

It is an arithmetic number, because the mean of its divisors is an integer number (3344455).

Almost surely, 2^6688909 is an apocalyptic number.

It is an amenable number.

6688909 is a deficient number, since it is larger than the sum of its proper divisors (1).

6688909 is an equidigital number, since it uses as much as digits as its factorization.

6688909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 6688909 is about 2586.2925201918. The cubic root of 6688909 is about 188.4162818017.

The spelling of 6688909 in words is "six million, six hundred eighty-eight thousand, nine hundred nine".