6656966809 has 4 divisors (see below), whose sum is σ = 6685537716. Its totient is φ = 6628395904.

The previous prime is 6656966779. The next prime is 6656966867. The reversal of 6656966809 is 9086696566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1240448400 + 5416518409 = 35220^2 + 73597^2 .

It is a cyclic number.

It is not a de Polignac number, because 6656966809 - 2¹⁵ = 6656934041 is a prime.

It is a super-2 number, since 2×6656966809² = 88630414192255284962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6656966509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14285104 + ... + 14285569.

It is an arithmetic number, because the mean of its divisors is an integer number (1671384429).

Almost surely, 2^6656966809 is an apocalyptic number.

It is an amenable number.

6656966809 is a deficient number, since it is larger than the sum of its proper divisors (28570907).

6656966809 is a wasteful number, since it uses less digits than its factorization.

6656966809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28570906.

The product of its (nonzero) digits is 25194240, while the sum is 61.

The square root of 6656966809 is about 81590.2372162258. The cubic root of 6656966809 is about 1881.1588231525.

The spelling of 6656966809 in words is "six billion, six hundred fifty-six million, nine hundred sixty-six thousand, eight hundred nine".