A:
Positive:
1 x 211321397 x 301887717 x 1243067119 x 177581311 x 67949571 x 370092177 x 97073997 x 5287
Negative:
-1 x -21132139-7 x -3018877-17 x -1243067-119 x -177581-311 x -67949-571 x -37009-2177 x -9707-3997 x -5287
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 21,132,139, it is easier to work with a table - it's called factoring from the outside in.
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 | 21,132,139 | |
| -1 | -21,132,139 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,132,139.
Example:
1 x 21,132,139 = 21,132,139
and
-1 x -21,132,139 = 21,132,139
Notice both answers equal 21,132,139
With that explanation out of the way, let's continue. Next, we take the number 21,132,139 and divide it by 2:
21,132,139 ÷ 2 = 10,566,069.5
If the quotient is a whole number, then 2 and 10,566,069.5 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 | 21,132,139 | |
| -1 | -21,132,139 |
Now, we try dividing 21,132,139 by 3:
21,132,139 ÷ 3 = 7,044,046.3333
If the quotient is a whole number, then 3 and 7,044,046.3333 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 | 21,132,139 | |
| -1 | -21,132,139 |
Let's try dividing by 4:
21,132,139 ÷ 4 = 5,283,034.75
If the quotient is a whole number, then 4 and 5,283,034.75 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 | 21,132,139 | |
| -1 | 21,132,139 |
If you did it right, you will end up with this table:
| 1 | 7 | 17 | 119 | 311 | 571 | 2,177 | 3,997 | 5,287 | 9,707 | 37,009 | 67,949 | 177,581 | 1,243,067 | 3,018,877 | 21,132,139 |
| -1 | -7 | -17 | -119 | -311 | -571 | -2,177 | -3,997 | -5,287 | -9,707 | -37,009 | -67,949 | -177,581 | -1,243,067 | -3,018,877 | -21,132,139 |
Here are some more numbers to try:
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