865620 has 96 divisors (see below), whose sum is σ = 3091200. Its totient is φ = 196992.

The previous prime is 865619. The next prime is 865637. The reversal of 865620 is 26568.

865620 is a `hidden beast` number, since 8 + 656 + 2 + 0 = 666.

865620 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3666 + ... + 3894.

It is an arithmetic number, because the mean of its divisors is an integer number (32200).

2⁸⁶⁵⁶²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 865620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1545600).

865620 is an abundant number, since it is smaller than the sum of its proper divisors (2225580).

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

865620 is a wasteful number, since it uses less digits than its factorization.

865620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 246 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 865620 is about 930.3870162465. The cubic root of 865620 is about 95.3035534915.

It can be divided in two parts, 865 and 620, that added together give a triangular number (1485 = T₅₄).

The spelling of 865620 in words is "eight hundred sixty-five thousand, six hundred twenty".