6660809 has 2 divisors, whose sum is σ = 6660810. Its totient is φ = 6660808.

The previous prime is 6660799. The next prime is 6660859. The reversal of 6660809 is 9080666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5895184 + 765625 = 2428^2 + 875^2 .

It is a cyclic number.

It is not a de Polignac number, because 6660809 - 2⁸ = 6660553 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (6660859) 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, 3330404 + 3330405.

It is an arithmetic number, because the mean of its divisors is an integer number (3330405).

Almost surely, 2^6660809 is an apocalyptic number.

It is an amenable number.

6660809 is a deficient number, since it is larger than the sum of its proper divisors (1).

6660809 is an equidigital number, since it uses as much as digits as its factorization.

6660809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 6660809 is about 2580.8543159194. The cubic root of 6660809 is about 188.1520668700.

The spelling of 6660809 in words is "six million, six hundred sixty thousand, eight hundred nine".