8666681 has 2 divisors, whose sum is σ = 8666682. Its totient is φ = 8666680.

The previous prime is 8666627. The next prime is 8666683. The reversal of 8666681 is 1866668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6295081 + 2371600 = 2509^2 + 1540^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8666681 is a prime.

It is a super-2 number, since 2×8666681² = 150222719111522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 8666683, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (8666683) 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, 4333340 + 4333341.

It is an arithmetic number, because the mean of its divisors is an integer number (4333341).

Almost surely, 2^8666681 is an apocalyptic number.

It is an amenable number.

8666681 is a deficient number, since it is larger than the sum of its proper divisors (1).

8666681 is an equidigital number, since it uses as much as digits as its factorization.

8666681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 41.

The square root of 8666681 is about 2943.9227231706. The cubic root of 8666681 is about 205.4081181627.

The spelling of 8666681 in words is "eight million, six hundred sixty-six thousand, six hundred eighty-one".