Q: What are the factor combinations of the number 642,565?

 A:
Positive:   1 x 6425655 x 1285137 x 9179511 x 5841535 x 1835955 x 1168377 x 8345385 x 1669
Negative: -1 x -642565-5 x -128513-7 x -91795-11 x -58415-35 x -18359-55 x -11683-77 x -8345-385 x -1669


How do I find the factor combinations of the number 642,565?

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 642,565, 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.

1 642,565
-1 -642,565

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 642,565.

Example:
1 x 642,565 = 642,565
and
-1 x -642,565 = 642,565
Notice both answers equal 642,565

With that explanation out of the way, let's continue. Next, we take the number 642,565 and divide it by 2:

642,565 ÷ 2 = 321,282.5

If the quotient is a whole number, then 2 and 321,282.5 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:

1 642,565
-1 -642,565

Now, we try dividing 642,565 by 3:

642,565 ÷ 3 = 214,188.3333

If the quotient is a whole number, then 3 and 214,188.3333 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:

1 642,565
-1 -642,565

Let's try dividing by 4:

642,565 ÷ 4 = 160,641.25

If the quotient is a whole number, then 4 and 160,641.25 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:

1 642,565
-1 642,565
Keep dividing by the next highest number until you cannot divide anymore.

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

157113555773851,6698,34511,68318,35958,41591,795128,513642,565
-1-5-7-11-35-55-77-385-1,669-8,345-11,683-18,359-58,415-91,795-128,513-642,565

More Examples

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