866118574722861 has 6 divisors (see below), whose sum is σ = 1251060163488590. Its totient is φ = 577412383148568.

The previous prime is 866118574722847. The next prime is 866118574722977. The reversal of 866118574722861 is 168227475811668.

866118574722861 is a `hidden beast` number, since 8 + 6 + 6 + 11 + 85 + 7 + 472 + 2 + 8 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 782462490545961 + 83656084176900 = 27972531^2 + 9146370^2 .

It is not a de Polignac number, because 866118574722861 - 2²⁵ = 866118541168429 is a prime.

It is a super-2 number, since 2×866118574722861² (a number of 31 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 866118574722861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866118574721861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 48117698595706 + ... + 48117698595723.

Almost surely, 2^{866118574722861} is an apocalyptic number.

It is an amenable number.

866118574722861 is a deficient number, since it is larger than the sum of its proper divisors (384941588765729).

866118574722861 is a wasteful number, since it uses less digits than its factorization.

866118574722861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96235397191435 (or 96235397191432 counting only the distinct ones).

The product of its digits is 433520640, while the sum is 72.

The spelling of 866118574722861 in words is "eight hundred sixty-six trillion, one hundred eighteen billion, five hundred seventy-four million, seven hundred twenty-two thousand, eight hundred sixty-one".