687115861 has 2 divisors, whose sum is σ = 687115862. Its totient is φ = 687115860.

The previous prime is 687115841. The next prime is 687115873. The reversal of 687115861 is 168511786.

687115861 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., 590781636 + 96334225 = 24306^2 + 9815^2 .

It is a cyclic number.

It is not a de Polignac number, because 687115861 - 2⁷ = 687115733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687115841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343557930 + 343557931.

It is an arithmetic number, because the mean of its divisors is an integer number (343557931).

Almost surely, 2^687115861 is an apocalyptic number.

It is an amenable number.

687115861 is a deficient number, since it is larger than the sum of its proper divisors (1).

687115861 is an equidigital number, since it uses as much as digits as its factorization.

687115861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 43.

The square root of 687115861 is about 26212.8949374158. The cubic root of 687115861 is about 882.4226720572.

The spelling of 687115861 in words is "six hundred eighty-seven million, one hundred fifteen thousand, eight hundred sixty-one".