865864581120 has 2176 divisors, whose sum is σ = 4058713128960. Its totient is φ = 169869312000.

The previous prime is 865864581097. The next prime is 865864581137. The reversal of 865864581120 is 21185468568.

865864581120 is a `hidden beast` number, since 8 + 6 + 58 + 6 + 4 + 581 + 1 + 2 + 0 = 666.

It is a super-2 number, since 2×865864581120² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

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, 21118648300 + ... + 21118648340.

Almost surely, 2^865864581120 is an apocalyptic number.

865864581120 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 865864581120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2029356564480).

865864581120 is an abundant number, since it is smaller than the sum of its proper divisors (3192848547840).

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

865864581120 is a wasteful number, since it uses less digits than its factorization.

865864581120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 3686400, while the sum is 54.

The spelling of 865864581120 in words is "eight hundred sixty-five billion, eight hundred sixty-four million, five hundred eighty-one thousand, one hundred twenty".