What are the divisors of 5157?

1, 3, 9, 27, 191, 573, 1719, 5157

There is a total of 8 positive divisors.
The sum of these divisors is 7680.
The arithmetic mean is 960.

8 odd divisors

1, 3, 9, 27, 191, 573, 1719, 5157

How to compute the divisors of 5157?

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 5157 by each of the numbers from 1 to 5157 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)

5157 / 1 = 5157 (the remainder is 0, so 1 is a divisor of 5157)
5157 / 2 = 2578.5 (the remainder is 1, so 2 is not a divisor of 5157)
5157 / 3 = 1719 (the remainder is 0, so 3 is a divisor of 5157)
...
5157 / 5156 = 1.0001939487975 (the remainder is 1, so 5156 is not a divisor of 5157)
5157 / 5157 = 1 (the remainder is 0, so 5157 is a divisor of 5157)

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 5157 (i.e. 71.812255221515). 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 $\frac{N}{d} = D$ )

5157 / 1 = 5157 (the remainder is 0, so 1 and 5157 are divisors of 5157)
5157 / 2 = 2578.5 (the remainder is 1, so 2 is not a divisor of 5157)
5157 / 3 = 1719 (the remainder is 0, so 3 and 1719 are divisors of 5157)
...
5157 / 70 = 73.671428571429 (the remainder is 47, so 70 is not a divisor of 5157)
5157 / 71 = 72.633802816901 (the remainder is 45, so 71 is not a divisor of 5157)