A:
Positive:
1 x 2110762129 x 72784931 x 68089153 x 398257443 x 47647899 x 234791537 x 137331643 x 12847
Negative:
-1 x -21107621-29 x -727849-31 x -680891-53 x -398257-443 x -47647-899 x -23479-1537 x -13733-1643 x -12847
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 21,107,621, 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 | 21,107,621 | |
| -1 | -21,107,621 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,107,621.
Example:
1 x 21,107,621 = 21,107,621
and
-1 x -21,107,621 = 21,107,621
Notice both answers equal 21,107,621
With that explanation out of the way, let's continue. Next, we take the number 21,107,621 and divide it by 2:
21,107,621 ÷ 2 = 10,553,810.5
If the quotient is a whole number, then 2 and 10,553,810.5 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 | 21,107,621 | |
| -1 | -21,107,621 |
Now, we try dividing 21,107,621 by 3:
21,107,621 ÷ 3 = 7,035,873.6667
If the quotient is a whole number, then 3 and 7,035,873.6667 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 | 21,107,621 | |
| -1 | -21,107,621 |
Let's try dividing by 4:
21,107,621 ÷ 4 = 5,276,905.25
If the quotient is a whole number, then 4 and 5,276,905.25 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 | 21,107,621 | |
| -1 | 21,107,621 |
If you did it right, you will end up with this table:
| 1 | 29 | 31 | 53 | 443 | 899 | 1,537 | 1,643 | 12,847 | 13,733 | 23,479 | 47,647 | 398,257 | 680,891 | 727,849 | 21,107,621 |
| -1 | -29 | -31 | -53 | -443 | -899 | -1,537 | -1,643 | -12,847 | -13,733 | -23,479 | -47,647 | -398,257 | -680,891 | -727,849 | -21,107,621 |
Here are some more numbers to try:
Try the factor calculator