6688888861 has 2 divisors, whose sum is σ = 6688888862. Its totient is φ = 6688888860.

The previous prime is 6688888813. The next prime is 6688888873. The reversal of 6688888861 is 1688888866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6688131961 + 756900 = 81781^2 + 870^2 .

It is a cyclic number.

It is not a de Polignac number, because 6688888861 - 2²⁵ = 6655334429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6688888961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3344444430 + 3344444431.

It is an arithmetic number, because the mean of its divisors is an integer number (3344444431).

Almost surely, 2^6688888861 is an apocalyptic number.

It is an amenable number.

6688888861 is a deficient number, since it is larger than the sum of its proper divisors (1).

6688888861 is an equidigital number, since it uses as much as digits as its factorization.

6688888861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56623104, while the sum is 67.

The square root of 6688888861 is about 81785.6274720687. The cubic root of 6688888861 is about 1884.1609270663.

The spelling of 6688888861 in words is "six billion, six hundred eighty-eight million, eight hundred eighty-eight thousand, eight hundred sixty-one".