6666766681 has 2 divisors, whose sum is σ = 6666766682. Its totient is φ = 6666766680.

The previous prime is 6666766669. The next prime is 6666766693. The reversal of 6666766681 is 1866676666.

It is a balanced prime because it is at equal distance from previous prime (6666766669) and next prime (6666766693).

It can be written as a sum of positive squares in only one way, i.e., 4831501081 + 1835265600 = 69509^2 + 42840^2 .

It is a cyclic number.

It is not a de Polignac number, because 6666766681 - 2⁵ = 6666766649 is a prime.

It is a super-2 number, since 2×6666766681² = 88891555957783511522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6666766621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3333383340 + 3333383341.

It is an arithmetic number, because the mean of its divisors is an integer number (3333383341).

Almost surely, 2^6666766681 is an apocalyptic number.

It is an amenable number.

6666766681 is a deficient number, since it is larger than the sum of its proper divisors (1).

6666766681 is an equidigital number, since it uses as much as digits as its factorization.

6666766681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15676416, while the sum is 58.

The square root of 6666766681 is about 81650.2705506846. The cubic root of 6666766681 is about 1882.0814694241.

The spelling of 6666766681 in words is "six billion, six hundred sixty-six million, seven hundred sixty-six thousand, six hundred eighty-one".