Q: What are the factor combinations of the number 20,643,515?

 A:
Positive:   1 x 206435155 x 4128703643 x 321053215 x 6421
Negative: -1 x -20643515-5 x -4128703-643 x -32105-3215 x -6421


How do I find the factor combinations of the number 20,643,515?

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 20,643,515, 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 20,643,515
-1 -20,643,515

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 20,643,515.

Example:
1 x 20,643,515 = 20,643,515
and
-1 x -20,643,515 = 20,643,515
Notice both answers equal 20,643,515

With that explanation out of the way, let's continue. Next, we take the number 20,643,515 and divide it by 2:

20,643,515 ÷ 2 = 10,321,757.5

If the quotient is a whole number, then 2 and 10,321,757.5 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 20,643,515
-1 -20,643,515

Now, we try dividing 20,643,515 by 3:

20,643,515 ÷ 3 = 6,881,171.6667

If the quotient is a whole number, then 3 and 6,881,171.6667 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 20,643,515
-1 -20,643,515

Let's try dividing by 4:

20,643,515 ÷ 4 = 5,160,878.75

If the quotient is a whole number, then 4 and 5,160,878.75 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 20,643,515
-1 20,643,515
Keep dividing by the next highest number until you cannot divide anymore.

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

156433,2156,42132,1054,128,70320,643,515
-1-5-643-3,215-6,421-32,105-4,128,703-20,643,515

More Examples

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