6660656609 has 2 divisors, whose sum is σ = 6660656610. Its totient is φ = 6660656608.

The previous prime is 6660656603. The next prime is 6660656711. The reversal of 6660656609 is 9066560666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4753413025 + 1907243584 = 68945^2 + 43672^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6660656609 is a prime.

It is not a weakly prime, because it can be changed into another prime (6660656603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3330328304 + 3330328305.

It is an arithmetic number, because the mean of its divisors is an integer number (3330328305).

Almost surely, 2^6660656609 is an apocalyptic number.

It is an amenable number.

6660656609 is a deficient number, since it is larger than the sum of its proper divisors (1).

6660656609 is an equidigital number, since it uses as much as digits as its factorization.

6660656609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2099520, while the sum is 50.

The square root of 6660656609 is about 81612.8458577447. The cubic root of 6660656609 is about 1881.5063196420.

The spelling of 6660656609 in words is "six billion, six hundred sixty million, six hundred fifty-six thousand, six hundred nine".