865220 has 12 divisors (see below), whose sum is σ = 1817004. Its totient is φ = 346080.

The previous prime is 865217. The next prime is 865231. The reversal of 865220 is 22568.

It is a happy number.

865220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 391876 + 473344 = 626^2 + 688^2 .

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21611 + ... + 21650.

It is an arithmetic number, because the mean of its divisors is an integer number (151417).

2⁸⁶⁵²²⁰ is an apocalyptic number.

It is an amenable number.

865220 is an abundant number, since it is smaller than the sum of its proper divisors (951784).

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

865220 is a wasteful number, since it uses less digits than its factorization.

865220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43270 (or 43268 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 865220 is about 930.1720271004. The cubic root of 865220 is about 95.2888714159.

Adding to 865220 its reverse (22568), we get a palindrome (887788).

The spelling of 865220 in words is "eight hundred sixty-five thousand, two hundred twenty".