861720677 has 2 divisors, whose sum is σ = 861720678. Its totient is φ = 861720676.

The previous prime is 861720647. The next prime is 861720697. The reversal of 861720677 is 776027168.

861720677 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 852289636 + 9431041 = 29194^2 + 3071^2 .

It is a cyclic number.

It is not a de Polignac number, because 861720677 - 2¹⁰ = 861719653 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861720617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430860338 + 430860339.

It is an arithmetic number, because the mean of its divisors is an integer number (430860339).

Almost surely, 2^861720677 is an apocalyptic number.

It is an amenable number.

861720677 is a deficient number, since it is larger than the sum of its proper divisors (1).

861720677 is an equidigital number, since it uses as much as digits as its factorization.

861720677 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 197568, while the sum is 44.

The square root of 861720677 is about 29355.0792368203. The cubic root of 861720677 is about 951.6023473545.

The spelling of 861720677 in words is "eight hundred sixty-one million, seven hundred twenty thousand, six hundred seventy-seven".