8666666681 has 4 divisors (see below), whose sum is σ = 8752475364. Its totient is φ = 8580858000.

The previous prime is 8666666677. The next prime is 8666666699. The reversal of 8666666681 is 1866666668.

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 4423447081 + 4243219600 = 66509^2 + 65140^2 .

It is a cyclic number.

It is not a de Polignac number, because 8666666681 - 2² = 8666666677 is a prime.

It is a super-2 number, since 2×8666666681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8666666681.

It is not an unprimeable number, because it can be changed into a prime (8666666381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42904190 + ... + 42904391.

It is an arithmetic number, because the mean of its divisors is an integer number (2188118841).

Almost surely, 2^8666666681 is an apocalyptic number.

It is an amenable number.

8666666681 is a deficient number, since it is larger than the sum of its proper divisors (85808683).

8666666681 is a wasteful number, since it uses less digits than its factorization.

8666666681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85808682.

The product of its digits is 17915904, while the sum is 59.

The square root of 8666666681 is about 93094.9337021086. The cubic root of 8666666681 is about 2054.0800503821.

The spelling of 8666666681 in words is "eight billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-one".