866802378338721 has 32 divisors (see below), whose sum is σ = 1400972432371200. Its totient is φ = 525304887362640.

The previous prime is 866802378338717. The next prime is 866802378338737. The reversal of 866802378338721 is 127833873208668.

866802378338721 is a `hidden beast` number, since 8 + 6 + 6 + 8 + 0 + 237 + 8 + 3 + 387 + 2 + 1 = 666.

866802378338721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 866802378338721 - 2² = 866802378338717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 866802378338721.

It is not an unprimeable number, because it can be changed into a prime (866802378338711) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77790771 + ... + 88232696.

It is an arithmetic number, because the mean of its divisors is an integer number (43780388511600).

Almost surely, 2^{866802378338721} is an apocalyptic number.

It is an amenable number.

866802378338721 is a deficient number, since it is larger than the sum of its proper divisors (534170054032479).

866802378338721 is a wasteful number, since it uses less digits than its factorization.

866802378338721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166041066 (or 166041060 counting only the distinct ones).

The product of its (nonzero) digits is 780337152, while the sum is 72.

The spelling of 866802378338721 in words is "eight hundred sixty-six trillion, eight hundred two billion, three hundred seventy-eight million, three hundred thirty-eight thousand, seven hundred twenty-one".