866786513604066 has 80 divisors (see below), whose sum is σ = 2118834719036640. Its totient is φ = 262659698723520.

The previous prime is 866786513604059. The next prime is 866786513604071. The reversal of 866786513604066 is 660406315687668.

866786513604066 is a `hidden beast` number, since 8 + 6 + 6 + 7 + 8 + 6 + 5 + 1 + 3 + 604 + 0 + 6 + 6 = 666.

It is a super-2 number, since 2×866786513604066² (a number of 31 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 866786513603985 and 866786513604003.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 162710830 + ... + 167953526.

It is an arithmetic number, because the mean of its divisors is an integer number (26485433987958).

Almost surely, 2^{866786513604066} is an apocalyptic number.

866786513604066 is an abundant number, since it is smaller than the sum of its proper divisors (1252048205432574).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

866786513604066 is a wasteful number, since it uses less digits than its factorization.

866786513604066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5335501 (or 5335492 counting only the distinct ones).

The product of its (nonzero) digits is 1254113280, while the sum is 72.

The spelling of 866786513604066 in words is "eight hundred sixty-six trillion, seven hundred eighty-six billion, five hundred thirteen million, six hundred four thousand, sixty-six".