865791220320 has 576 divisors, whose sum is σ = 3218842658304. Its totient is φ = 210651217920.

The previous prime is 865791220277. The next prime is 865791220337. The reversal of 865791220320 is 23022197568.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 655405260 + ... + 655406580.

It is an arithmetic number, because the mean of its divisors is an integer number (5588268504).

Almost surely, 2^865791220320 is an apocalyptic number.

865791220320 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 865791220320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1609421329152).

865791220320 is an abundant number, since it is smaller than the sum of its proper divisors (2353051437984).

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

865791220320 is a wasteful number, since it uses less digits than its factorization.

865791220320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1735 (or 1724 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 865791220320 in words is "eight hundred sixty-five billion, seven hundred ninety-one million, two hundred twenty thousand, three hundred twenty".