865171440 has 360 divisors, whose sum is σ = 3423597840. Its totient is φ = 195213312.

The previous prime is 865171393. The next prime is 865171451. The reversal of 865171440 is 44171568.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 865171395 and 865171404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4833271 + ... + 4833449.

It is an arithmetic number, because the mean of its divisors is an integer number (9509994).

Almost surely, 2^865171440 is an apocalyptic number.

865171440 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 865171440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1711798920).

865171440 is an abundant number, since it is smaller than the sum of its proper divisors (2558426400).

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

865171440 is a wasteful number, since it uses less digits than its factorization.

865171440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 349 (or 333 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 865171440 is about 29413.7967627438. The cubic root of 865171440 is about 952.8708870396.

The spelling of 865171440 in words is "eight hundred sixty-five million, one hundred seventy-one thousand, four hundred forty".