6666666681 has 8 divisors (see below), whose sum is σ = 8910105120. Its totient is φ = 4433836352.

The previous prime is 6666666661. The next prime is 6666666757. The reversal of 6666666681 is 1866666666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6666666681 - 2⁹ = 6666666169 is a prime.

It is a super-2 number, since 2×6666666681² = 88888889271111111522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6666666631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2650560 + ... + 2653073.

It is an arithmetic number, because the mean of its divisors is an integer number (1113763140).

Almost surely, 2^6666666681 is an apocalyptic number.

It is an amenable number.

6666666681 is a deficient number, since it is larger than the sum of its proper divisors (2243438439).

6666666681 is a wasteful number, since it uses less digits than its factorization.

6666666681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5304055.

The product of its digits is 13436928, while the sum is 57.

The square root of 6666666681 is about 81649.6581805460. The cubic root of 6666666681 is about 1882.0720591109.

The spelling of 6666666681 in words is "six billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-one".