Q: What are the factor combinations of the number 128,617,245?

 A:
Positive:   1 x 1286172453 x 428724155 x 257234499 x 1429080515 x 857448345 x 2858161
Negative: -1 x -128617245-3 x -42872415-5 x -25723449-9 x -14290805-15 x -8574483-45 x -2858161


How do I find the factor combinations of the number 128,617,245?

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 128,617,245, 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.

1 128,617,245
-1 -128,617,245

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 128,617,245.

Example:
1 x 128,617,245 = 128,617,245
and
-1 x -128,617,245 = 128,617,245
Notice both answers equal 128,617,245

With that explanation out of the way, let's continue. Next, we take the number 128,617,245 and divide it by 2:

128,617,245 ÷ 2 = 64,308,622.5

If the quotient is a whole number, then 2 and 64,308,622.5 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:

1 128,617,245
-1 -128,617,245

Now, we try dividing 128,617,245 by 3:

128,617,245 ÷ 3 = 42,872,415

If the quotient is a whole number, then 3 and 42,872,415 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 3 42,872,415 128,617,245
-1 -3 -42,872,415 -128,617,245

Let's try dividing by 4:

128,617,245 ÷ 4 = 32,154,311.25

If the quotient is a whole number, then 4 and 32,154,311.25 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 3 42,872,415 128,617,245
-1 -3 -42,872,415 128,617,245
Keep dividing by the next highest number until you cannot divide anymore.

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

135915452,858,1618,574,48314,290,80525,723,44942,872,415128,617,245
-1-3-5-9-15-45-2,858,161-8,574,483-14,290,805-25,723,449-42,872,415-128,617,245

More Examples

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