What are the divisors of 761?

1, 761

There is a total of 2 positive divisors.
The sum of these divisors is 762.
The arithmetic mean is 381.

2 odd divisors

1, 761

How to compute the divisors of 761?

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 761 by each of the numbers from 1 to 761 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)

761 / 1 = 761 (the remainder is 0, so 1 is a divisor of 761)
761 / 2 = 380.5 (the remainder is 1, so 2 is not a divisor of 761)
761 / 3 = 253.66666666667 (the remainder is 2, so 3 is not a divisor of 761)
...
761 / 760 = 1.0013157894737 (the remainder is 1, so 760 is not a divisor of 761)
761 / 761 = 1 (the remainder is 0, so 761 is a divisor of 761)

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 761 (i.e. 27.586228448267). 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 $\frac{N}{d} = D$ )

761 / 1 = 761 (the remainder is 0, so 1 and 761 are divisors of 761)
761 / 2 = 380.5 (the remainder is 1, so 2 is not a divisor of 761)
761 / 3 = 253.66666666667 (the remainder is 2, so 3 is not a divisor of 761)
...
761 / 26 = 29.269230769231 (the remainder is 7, so 26 is not a divisor of 761)
761 / 27 = 28.185185185185 (the remainder is 5, so 27 is not a divisor of 761)