Q: What are the factor combinations of the number 21,659?

 A:
Positive:   1 x 2165911 x 1969121 x 179
Negative: -1 x -21659-11 x -1969-121 x -179


How do I find the factor combinations of the number 21,659?

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 21,659, 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 21,659
-1 -21,659

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 21,659.

Example:
1 x 21,659 = 21,659
and
-1 x -21,659 = 21,659
Notice both answers equal 21,659

With that explanation out of the way, let's continue. Next, we take the number 21,659 and divide it by 2:

21,659 ÷ 2 = 10,829.5

If the quotient is a whole number, then 2 and 10,829.5 are factors. In this case, the quotient is not a whole number. Don't write anything down and try the next divisor.

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

1 21,659
-1 -21,659

Now, we try dividing 21,659 by 3:

21,659 ÷ 3 = 7,219.6667

If the quotient is a whole number, then 3 and 7,219.6667 are factors. In this case, the quotient is not a whole number. Don't write anything down and try the next divisor.

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

1 21,659
-1 -21,659

Let's try dividing by 4:

21,659 ÷ 4 = 5,414.75

If the quotient is a whole number, then 4 and 5,414.75 are factors. In this case, the quotient is not a whole number. Don't write anything down and try the next divisor.

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

1 21,659
-1 21,659
Keep dividing by the next highest number until you cannot divide anymore.

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

1111211791,96921,659
-1-11-121-179-1,969-21,659

More Examples

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