A:
Positive:
1 x 210788955 x 421577917 x 123993553 x 39771585 x 247987265 x 79543901 x 233954505 x 4679
Negative:
-1 x -21078895-5 x -4215779-17 x -1239935-53 x -397715-85 x -247987-265 x -79543-901 x -23395-4505 x -4679
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 21,078,895, 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 | 21,078,895 | |
| -1 | -21,078,895 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,078,895.
Example:
1 x 21,078,895 = 21,078,895
and
-1 x -21,078,895 = 21,078,895
Notice both answers equal 21,078,895
With that explanation out of the way, let's continue. Next, we take the number 21,078,895 and divide it by 2:
21,078,895 ÷ 2 = 10,539,447.5
If the quotient is a whole number, then 2 and 10,539,447.5 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 | 21,078,895 | |
| -1 | -21,078,895 |
Now, we try dividing 21,078,895 by 3:
21,078,895 ÷ 3 = 7,026,298.3333
If the quotient is a whole number, then 3 and 7,026,298.3333 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 | 21,078,895 | |
| -1 | -21,078,895 |
Let's try dividing by 4:
21,078,895 ÷ 4 = 5,269,723.75
If the quotient is a whole number, then 4 and 5,269,723.75 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 | 21,078,895 | |
| -1 | 21,078,895 |
If you did it right, you will end up with this table:
| 1 | 5 | 17 | 53 | 85 | 265 | 901 | 4,505 | 4,679 | 23,395 | 79,543 | 247,987 | 397,715 | 1,239,935 | 4,215,779 | 21,078,895 |
| -1 | -5 | -17 | -53 | -85 | -265 | -901 | -4,505 | -4,679 | -23,395 | -79,543 | -247,987 | -397,715 | -1,239,935 | -4,215,779 | -21,078,895 |
Here are some more numbers to try:
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