Q: What are the factor combinations of the number 18,751,890?

 A:
Positive:   1 x 187518902 x 93759453 x 62506305 x 37503786 x 312531510 x 187518915 x 125012630 x 625063
Negative: -1 x -18751890-2 x -9375945-3 x -6250630-5 x -3750378-6 x -3125315-10 x -1875189-15 x -1250126-30 x -625063


How do I find the factor combinations of the number 18,751,890?

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 18,751,890, 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 18,751,890
-1 -18,751,890

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 18,751,890.

Example:
1 x 18,751,890 = 18,751,890
and
-1 x -18,751,890 = 18,751,890
Notice both answers equal 18,751,890

With that explanation out of the way, let's continue. Next, we take the number 18,751,890 and divide it by 2:

18,751,890 ÷ 2 = 9,375,945

If the quotient is a whole number, then 2 and 9,375,945 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 9,375,945 18,751,890
-1 -2 -9,375,945 -18,751,890

Now, we try dividing 18,751,890 by 3:

18,751,890 ÷ 3 = 6,250,630

If the quotient is a whole number, then 3 and 6,250,630 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 6,250,630 9,375,945 18,751,890
-1 -2 -3 -6,250,630 -9,375,945 -18,751,890

Let's try dividing by 4:

18,751,890 ÷ 4 = 4,687,972.5

If the quotient is a whole number, then 4 and 4,687,972.5 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 2 3 6,250,630 9,375,945 18,751,890
-1 -2 -3 -6,250,630 -9,375,945 18,751,890
Keep dividing by the next highest number until you cannot divide anymore.

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

12356101530625,0631,250,1261,875,1893,125,3153,750,3786,250,6309,375,94518,751,890
-1-2-3-5-6-10-15-30-625,063-1,250,126-1,875,189-3,125,315-3,750,378-6,250,630-9,375,945-18,751,890

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