What are the divisors of 1295?

1, 5, 7, 35, 37, 185, 259, 1295

There is a total of 8 positive divisors.
The sum of these divisors is 1824.
The arithmetic mean is 228.

8 odd divisors

1, 5, 7, 35, 37, 185, 259, 1295

How to compute the divisors of 1295?

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 1295 by each of the numbers from 1 to 1295 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)

1295 / 1 = 1295 (the remainder is 0, so 1 is a divisor of 1295)
1295 / 2 = 647.5 (the remainder is 1, so 2 is not a divisor of 1295)
1295 / 3 = 431.66666666667 (the remainder is 2, so 3 is not a divisor of 1295)
...
1295 / 1294 = 1.000772797527 (the remainder is 1, so 1294 is not a divisor of 1295)
1295 / 1295 = 1 (the remainder is 0, so 1295 is a divisor of 1295)

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 1295 (i.e. 35.986108430893). 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 $\frac{N}{d} = D$ )

1295 / 1 = 1295 (the remainder is 0, so 1 and 1295 are divisors of 1295)
1295 / 2 = 647.5 (the remainder is 1, so 2 is not a divisor of 1295)
1295 / 3 = 431.66666666667 (the remainder is 2, so 3 is not a divisor of 1295)
...
1295 / 34 = 38.088235294118 (the remainder is 3, so 34 is not a divisor of 1295)
1295 / 35 = 37 (the remainder is 0, so 35 and 37 are divisors of 1295)