866443864562661 has 16 divisors (see below), whose sum is σ = 1440322268364288. Its totient is φ = 450100708863600.

The previous prime is 866443864562651. The next prime is 866443864562701. The reversal of 866443864562661 is 166265468344668.

It is not a de Polignac number, because 866443864562661 - 2¹¹ = 866443864560613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866443864562651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1875419620035 + ... + 1875419620496.

It is an arithmetic number, because the mean of its divisors is an integer number (90020141772768).

Almost surely, 2^{866443864562661} is an apocalyptic number.

It is an amenable number.

866443864562661 is a deficient number, since it is larger than the sum of its proper divisors (573878403801627).

866443864562661 is a wasteful number, since it uses less digits than its factorization.

866443864562661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3750839240552.

The product of its digits is 5733089280, while the sum is 75.

The spelling of 866443864562661 in words is "eight hundred sixty-six trillion, four hundred forty-three billion, eight hundred sixty-four million, five hundred sixty-two thousand, six hundred sixty-one".