# What's the quickest way to determine the proper divisors of a number by hand?

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For example, the proper divisors of 130 are 1, 2, 5, 10, 13, 26, and 65 - are there any patterns I could use to figure those out quickly?

For example, the proper divisors of 130 are 1, 2, 5, 10, 13, 26, and 65 - are there any patterns I could use to figure those out quickly?

##### 1 Answer

Not much, but here are some ways to find some of them:

#### Explanation:

Let

If

If the sum of

If the last two digits are

If the last digit is

If it's divisible by

If

If the sum of

If the last digit is

Rules for

Hope this helps.