866158015648861 has 12 divisors (see below), whose sum is σ = 987274474396320. Its totient is φ = 757449924613200.

The previous prime is 866158015648859. The next prime is 866158015648867. The reversal of 866158015648861 is 168846510851668.

It is a happy number.

It is not a de Polignac number, because 866158015648861 - 2¹ = 866158015648859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866158015648867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 134873558865 + ... + 134873565286.

It is an arithmetic number, because the mean of its divisors is an integer number (82272872866360).

Almost surely, 2^{866158015648861} is an apocalyptic number.

It is an amenable number.

866158015648861 is a deficient number, since it is larger than the sum of its proper divisors (121116458747459).

866158015648861 is a wasteful number, since it uses less digits than its factorization.

866158015648861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269747124196 (or 269747124183 counting only the distinct ones).

The product of its (nonzero) digits is 530841600, while the sum is 73.

The spelling of 866158015648861 in words is "eight hundred sixty-six trillion, one hundred fifty-eight billion, fifteen million, six hundred forty-eight thousand, eight hundred sixty-one".