6647909 has 2 divisors, whose sum is σ = 6647910. Its totient is φ = 6647908.

The previous prime is 6647899. The next prime is 6647911. The reversal of 6647909 is 9097466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6400900 + 247009 = 2530^2 + 497^2 .

It is a cyclic number.

It is not a de Polignac number, because 6647909 - 2⁸ = 6647653 is a prime.

Together with 6647911, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6647939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3323954 + 3323955.

It is an arithmetic number, because the mean of its divisors is an integer number (3323955).

Almost surely, 2^6647909 is an apocalyptic number.

It is an amenable number.

6647909 is a deficient number, since it is larger than the sum of its proper divisors (1).

6647909 is an equidigital number, since it uses as much as digits as its factorization.

6647909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 41.

The square root of 6647909 is about 2578.3539322599. The cubic root of 6647909 is about 188.0305235636.

The spelling of 6647909 in words is "six million, six hundred forty-seven thousand, nine hundred nine".