What are the divisors of 4955?

1, 5, 991, 4955

There is a total of 4 positive divisors.
The sum of these divisors is 5952.
The arithmetic mean is 1488.

4 odd divisors

1, 5, 991, 4955

How to compute the divisors of 4955?

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 4955 by each of the numbers from 1 to 4955 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)

4955 / 1 = 4955 (the remainder is 0, so 1 is a divisor of 4955)
4955 / 2 = 2477.5 (the remainder is 1, so 2 is not a divisor of 4955)
4955 / 3 = 1651.6666666667 (the remainder is 2, so 3 is not a divisor of 4955)
...
4955 / 4954 = 1.0002018570852 (the remainder is 1, so 4954 is not a divisor of 4955)
4955 / 4955 = 1 (the remainder is 0, so 4955 is a divisor of 4955)

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 4955 (i.e. 70.391760881512). 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 $\frac{N}{d} = D$ )

4955 / 1 = 4955 (the remainder is 0, so 1 and 4955 are divisors of 4955)
4955 / 2 = 2477.5 (the remainder is 1, so 2 is not a divisor of 4955)
4955 / 3 = 1651.6666666667 (the remainder is 2, so 3 is not a divisor of 4955)
...
4955 / 69 = 71.811594202899 (the remainder is 56, so 69 is not a divisor of 4955)
4955 / 70 = 70.785714285714 (the remainder is 55, so 70 is not a divisor of 4955)