Q: What are the factor combinations of the number 678,821?

 A:
Positive:   1 x 67882111 x 6171113 x 5221747 x 14443101 x 6721143 x 4747517 x 1313611 x 1111
Negative: -1 x -678821-11 x -61711-13 x -52217-47 x -14443-101 x -6721-143 x -4747-517 x -1313-611 x -1111


How do I find the factor combinations of the number 678,821?

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 678,821, 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.

1 678,821
-1 -678,821

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 678,821.

Example:
1 x 678,821 = 678,821
and
-1 x -678,821 = 678,821
Notice both answers equal 678,821

With that explanation out of the way, let's continue. Next, we take the number 678,821 and divide it by 2:

678,821 ÷ 2 = 339,410.5

If the quotient is a whole number, then 2 and 339,410.5 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:

1 678,821
-1 -678,821

Now, we try dividing 678,821 by 3:

678,821 ÷ 3 = 226,273.6667

If the quotient is a whole number, then 3 and 226,273.6667 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:

1 678,821
-1 -678,821

Let's try dividing by 4:

678,821 ÷ 4 = 169,705.25

If the quotient is a whole number, then 4 and 169,705.25 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:

1 678,821
-1 678,821
Keep dividing by the next highest number until you cannot divide anymore.

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

11113471011435176111,1111,3134,7476,72114,44352,21761,711678,821
-1-11-13-47-101-143-517-611-1,111-1,313-4,747-6,721-14,443-52,217-61,711-678,821

More Examples

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