865520 has 40 divisors (see below), whose sum is σ = 2083200. Its totient is φ = 334080.

The previous prime is 865511. The next prime is 865537. The reversal of 865520 is 25568.

865520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 865520.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2306 + ... + 2654.

It is an arithmetic number, because the mean of its divisors is an integer number (52080).

2⁸⁶⁵⁵²⁰ is an apocalyptic number.

865520 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 865520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1041600).

865520 is an abundant number, since it is smaller than the sum of its proper divisors (1217680).

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

865520 is a wasteful number, since it uses less digits than its factorization.

865520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393 (or 387 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 865520 is about 930.3332736176. Note that the first 3 decimals coincide. The cubic root of 865520 is about 95.2998833967.

The spelling of 865520 in words is "eight hundred sixty-five thousand, five hundred twenty".