Q: What are the factor combinations of the number 20,688?

 A:
Positive:   1 x 206882 x 103443 x 68964 x 51726 x 34488 x 258612 x 172416 x 129324 x 86248 x 431
Negative: -1 x -20688-2 x -10344-3 x -6896-4 x -5172-6 x -3448-8 x -2586-12 x -1724-16 x -1293-24 x -862-48 x -431


How do I find the factor combinations of the number 20,688?

Unfortunately, there's not simple formula to identifying all of the factors of a number and it can be a tedious process when trying to identify the divisors of larger numbers. To find the factor combinations of the number 20,688, it is easier to work with a table - it's called factoring from the outside in.

Outside in Factoring

We start by creating a table and writing 1 on the left side and then the number we're trying to find the factors for on the right side in a table. Then, below that, write the numbers as a negative as well.

1 20,688
-1 -20,688

Why are the negative numbers included?

When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 20,688.

Example:
1 x 20,688 = 20,688
and
-1 x -20,688 = 20,688
Notice both answers equal 20,688

With that explanation out of the way, let's continue. Next, we take the number 20,688 and divide it by 2:

20,688 ÷ 2 = 10,344

If the quotient is a whole number, then 2 and 10,344 are factors. In this case, the quotient is a whole number. Write them in the table inside the other two factors like the below example. Don't forget to write the negative numbers too!

Here is what our table should look like at this step:

1 2 10,344 20,688
-1 -2 -10,344 -20,688

Now, we try dividing 20,688 by 3:

20,688 ÷ 3 = 6,896

If the quotient is a whole number, then 3 and 6,896 are factors. In this case, the quotient is a whole number. Write them in the table inside the other two factors like the below example. Don't forget to write the negative numbers too!

Here is what our table should look like at this step:

1 2 3 6,896 10,344 20,688
-1 -2 -3 -6,896 -10,344 -20,688

Let's try dividing by 4:

20,688 ÷ 4 = 5,172

If the quotient is a whole number, then 4 and 5,172 are factors. In this case, the quotient is a whole number. Write them in the table inside the other two factors like the below example. Don't forget to write the negative numbers too!

Here is what our table should look like at this step:

1 2 3 4 5,172 6,896 10,344 20,688
-1 -2 -3 -4 -5,172 -6,896 -10,344 20,688
Keep dividing by the next highest number until you cannot divide anymore.

If you did it right, you will end up with this table:

123468121624484318621,2931,7242,5863,4485,1726,89610,34420,688
-1-2-3-4-6-8-12-16-24-48-431-862-1,293-1,724-2,586-3,448-5,172-6,896-10,344-20,688

More Examples

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