6666666666681 has 32 divisors (see below), whose sum is σ = 10368135289600. Its totient is φ = 3808757901312.

The previous prime is 6666666666629. The next prime is 6666666666683. The reversal of 6666666666681 is 1866666666666.

It is not a de Polignac number, because 6666666666681 - 2¹⁰ = 6666666665657 is a prime.

It is a super-2 number, since 2×6666666666681² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6666666666683) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4489011 + ... + 5786583.

It is an arithmetic number, because the mean of its divisors is an integer number (324004227800).

Almost surely, 2^{6666666666681} is an apocalyptic number.

It is an amenable number.

6666666666681 is a deficient number, since it is larger than the sum of its proper divisors (3701468622919).

6666666666681 is a wasteful number, since it uses less digits than its factorization.

6666666666681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1302590 (or 1302576 counting only the distinct ones).

The product of its digits is 2902376448, while the sum is 75.

The spelling of 6666666666681 in words is "six trillion, six hundred sixty-six billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-one".