866844 has 54 divisors (see below), whose sum is σ = 2420600. Its totient is φ = 261360.

The previous prime is 866843. The next prime is 866849. The reversal of 866844 is 448668.

866844 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 (36).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 866799 and 866808.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 866844.

It is not an unprimeable number, because it can be changed into a prime (866843) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4257 + ... + 4455.

2⁸⁶⁶⁸⁴⁴ 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 866844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1210300).

866844 is an abundant number, since it is smaller than the sum of its proper divisors (1553756).

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

866844 is a wasteful number, since it uses less digits than its factorization.

866844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231 (or 215 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 866844 is about 931.0445746579. The cubic root of 866844 is about 95.3484525659.

The spelling of 866844 in words is "eight hundred sixty-six thousand, eight hundred forty-four".