Q: What are the factor combinations of the number 21,641,021?

 A:
Positive:   1 x 21641021103 x 210107163 x 1327671289 x 16789
Negative: -1 x -21641021-103 x -210107-163 x -132767-1289 x -16789


How do I find the factor combinations of the number 21,641,021?

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 21,641,021, 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 21,641,021
-1 -21,641,021

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 21,641,021.

Example:
1 x 21,641,021 = 21,641,021
and
-1 x -21,641,021 = 21,641,021
Notice both answers equal 21,641,021

With that explanation out of the way, let's continue. Next, we take the number 21,641,021 and divide it by 2:

21,641,021 ÷ 2 = 10,820,510.5

If the quotient is a whole number, then 2 and 10,820,510.5 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 21,641,021
-1 -21,641,021

Now, we try dividing 21,641,021 by 3:

21,641,021 ÷ 3 = 7,213,673.6667

If the quotient is a whole number, then 3 and 7,213,673.6667 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 21,641,021
-1 -21,641,021

Let's try dividing by 4:

21,641,021 ÷ 4 = 5,410,255.25

If the quotient is a whole number, then 4 and 5,410,255.25 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 21,641,021
-1 21,641,021
Keep dividing by the next highest number until you cannot divide anymore.

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

11031631,28916,789132,767210,10721,641,021
-1-103-163-1,289-16,789-132,767-210,107-21,641,021

More Examples

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