865305866880 has 2560 divisors, whose sum is σ = 4031461969920. Its totient is φ = 171992678400.

The previous prime is 865305866839. The next prime is 865305866917. The reversal of 865305866880 is 88668503568.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 8920678992 + ... + 8920679088.

It is an arithmetic number, because the mean of its divisors is an integer number (1574789832).

Almost surely, 2^865305866880 is an apocalyptic number.

865305866880 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 865305866880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2015730984960).

865305866880 is an abundant number, since it is smaller than the sum of its proper divisors (3166156103040).

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

865305866880 is a wasteful number, since it uses less digits than its factorization.

865305866880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 219 counting only the distinct ones).

The product of its (nonzero) digits is 66355200, while the sum is 63.

The spelling of 865305866880 in words is "eight hundred sixty-five billion, three hundred five million, eight hundred sixty-six thousand, eight hundred eighty".