What are the divisors of 5389?

1, 17, 317, 5389

There is a total of 4 positive divisors.
The sum of these divisors is 5724.
The arithmetic mean is 1431.

4 odd divisors

1, 17, 317, 5389

How to compute the divisors of 5389?

A number N is said to be divisible by a number M (with M non-zero) if, when we divide N by M, the remainder of the division is zero.

$N mod M = 0$

Brute force algorithm

We could start by using a brute-force method which would involve dividing 5389 by each of the numbers from 1 to 5389 to determine which ones have a remainder equal to 0.

$Remainder = N - (M \times ⌊ \frac{N}{M} ⌋)$

(where $⌊ \frac{N}{M} ⌋$ is the integer part of the quotient)

5389 / 1 = 5389 (the remainder is 0, so 1 is a divisor of 5389)
5389 / 2 = 2694.5 (the remainder is 1, so 2 is not a divisor of 5389)
5389 / 3 = 1796.3333333333 (the remainder is 1, so 3 is not a divisor of 5389)
...
5389 / 5388 = 1.0001855976244 (the remainder is 1, so 5388 is not a divisor of 5389)
5389 / 5389 = 1 (the remainder is 0, so 5389 is a divisor of 5389)

Improved algorithm using square-root

However, there is another slightly better approach that reduces the number of iterations by testing only integers less than or equal to the square root of 5389 (i.e. 73.409808608932). Indeed, if a number N has a divisor D greater than its square root, then there is necessarily a smaller divisor d such that:

$D \times d = N$

(thus, if $\frac{N}{D} = d$ , then $\frac{N}{d} = D$ )

5389 / 1 = 5389 (the remainder is 0, so 1 and 5389 are divisors of 5389)
5389 / 2 = 2694.5 (the remainder is 1, so 2 is not a divisor of 5389)
5389 / 3 = 1796.3333333333 (the remainder is 1, so 3 is not a divisor of 5389)
...
5389 / 72 = 74.847222222222 (the remainder is 61, so 72 is not a divisor of 5389)
5389 / 73 = 73.821917808219 (the remainder is 60, so 73 is not a divisor of 5389)