861688688771 has 2 divisors, whose sum is σ = 861688688772. Its totient is φ = 861688688770.

The previous prime is 861688688753. The next prime is 861688688779. The reversal of 861688688771 is 177886886168.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861688688771 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (861688688779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430844344385 + 430844344386.

It is an arithmetic number, because the mean of its divisors is an integer number (430844344386).

Almost surely, 2^861688688771 is an apocalyptic number.

861688688771 is a deficient number, since it is larger than the sum of its proper divisors (1).

861688688771 is an equidigital number, since it uses as much as digits as its factorization.

861688688771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 346816512, while the sum is 74.

The spelling of 861688688771 in words is "eight hundred sixty-one billion, six hundred eighty-eight million, six hundred eighty-eight thousand, seven hundred seventy-one".