8656663681 has 4 divisors (see below), whose sum is σ = 8819997012. Its totient is φ = 8493330352.

The previous prime is 8656663669. The next prime is 8656663703. The reversal of 8656663681 is 1863666568.

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 6632473600 + 2024190081 = 81440^2 + 44991^2 .

It is a cyclic number.

It is not a de Polignac number, because 8656663681 - 2⁷ = 8656663553 is a prime.

It is a super-2 number, since 2×8656663681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8656663621) 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, 81666586 + ... + 81666691.

It is an arithmetic number, because the mean of its divisors is an integer number (2204999253).

Almost surely, 2^8656663681 is an apocalyptic number.

It is an amenable number.

8656663681 is a deficient number, since it is larger than the sum of its proper divisors (163333331).

8656663681 is a wasteful number, since it uses less digits than its factorization.

8656663681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163333330.

The product of its digits is 7464960, while the sum is 55.

The square root of 8656663681 is about 93041.1934628958. The cubic root of 8656663681 is about 2053.2894783501.

The spelling of 8656663681 in words is "eight billion, six hundred fifty-six million, six hundred sixty-three thousand, six hundred eighty-one".