866609810220 has 384 divisors, whose sum is σ = 3205736497152. Its totient is φ = 169348608000.

The previous prime is 866609810149. The next prime is 866609810249. The reversal of 866609810220 is 22018906668.

It is a happy number.

866609810220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 866609810220.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 121183645 + ... + 121190795.

It is an arithmetic number, because the mean of its divisors is an integer number (8348272128).

Almost surely, 2^866609810220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 866609810220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1602868248576).

866609810220 is an abundant number, since it is smaller than the sum of its proper divisors (2339126686932).

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

866609810220 is a wasteful number, since it uses less digits than its factorization.

866609810220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8741 (or 8739 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 48.

The spelling of 866609810220 in words is "eight hundred sixty-six billion, six hundred nine million, eight hundred ten thousand, two hundred twenty".