861408866 has 24 divisors (see below), whose sum is σ = 1348999380. Its totient is φ = 412037696.

The previous prime is 861408859. The next prime is 861408881. The reversal of 861408866 is 668804168.

It can be written as a sum of positive squares in 6 ways, for example, as 861129025 + 279841 = 29345^2 + 529^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 861408866.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2939816 + ... + 2940108.

Almost surely, 2^861408866 is an apocalyptic number.

861408866 is a deficient number, since it is larger than the sum of its proper divisors (487590514).

861408866 is a wasteful number, since it uses less digits than its factorization.

861408866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 790 (or 497 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 47.

The square root of 861408866 is about 29349.7677333229. The cubic root of 861408866 is about 951.4875553716.

The spelling of 861408866 in words is "eight hundred sixty-one million, four hundred eight thousand, eight hundred sixty-six".