Q: What are the factor combinations of the number 721,105?

 A:
Positive:   1 x 7211055 x 1442217 x 10301511 x 6555535 x 2060355 x 1311177 x 9365385 x 1873
Negative: -1 x -721105-5 x -144221-7 x -103015-11 x -65555-35 x -20603-55 x -13111-77 x -9365-385 x -1873


How do I find the factor combinations of the number 721,105?

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 721,105, 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.

1 721,105
-1 -721,105

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 721,105.

Example:
1 x 721,105 = 721,105
and
-1 x -721,105 = 721,105
Notice both answers equal 721,105

With that explanation out of the way, let's continue. Next, we take the number 721,105 and divide it by 2:

721,105 ÷ 2 = 360,552.5

If the quotient is a whole number, then 2 and 360,552.5 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:

1 721,105
-1 -721,105

Now, we try dividing 721,105 by 3:

721,105 ÷ 3 = 240,368.3333

If the quotient is a whole number, then 3 and 240,368.3333 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:

1 721,105
-1 -721,105

Let's try dividing by 4:

721,105 ÷ 4 = 180,276.25

If the quotient is a whole number, then 4 and 180,276.25 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:

1 721,105
-1 721,105
Keep dividing by the next highest number until you cannot divide anymore.

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

157113555773851,8739,36513,11120,60365,555103,015144,221721,105
-1-5-7-11-35-55-77-385-1,873-9,365-13,111-20,603-65,555-103,015-144,221-721,105

More Examples

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