What are the divisors of 1417?

1, 13, 109, 1417

There is a total of 4 positive divisors.
The sum of these divisors is 1540.
The arithmetic mean is 385.

4 odd divisors

1, 13, 109, 1417

How to compute the divisors of 1417?

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 1417 by each of the numbers from 1 to 1417 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)

1417 / 1 = 1417 (the remainder is 0, so 1 is a divisor of 1417)
1417 / 2 = 708.5 (the remainder is 1, so 2 is not a divisor of 1417)
1417 / 3 = 472.33333333333 (the remainder is 1, so 3 is not a divisor of 1417)
...
1417 / 1416 = 1.0007062146893 (the remainder is 1, so 1416 is not a divisor of 1417)
1417 / 1417 = 1 (the remainder is 0, so 1417 is a divisor of 1417)

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 1417 (i.e. 37.643060449437). 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 $\frac{N}{d} = D$ )

1417 / 1 = 1417 (the remainder is 0, so 1 and 1417 are divisors of 1417)
1417 / 2 = 708.5 (the remainder is 1, so 2 is not a divisor of 1417)
1417 / 3 = 472.33333333333 (the remainder is 1, so 3 is not a divisor of 1417)
...
1417 / 36 = 39.361111111111 (the remainder is 13, so 36 is not a divisor of 1417)
1417 / 37 = 38.297297297297 (the remainder is 11, so 37 is not a divisor of 1417)