A:
Positive:
1 x 211873555 x 42374717 x 302676517 x 124631535 x 60535349 x 43239585 x 249263119 x 178045245 x 86479595 x 35609833 x 254354165 x 5087
Negative:
-1 x -21187355-5 x -4237471-7 x -3026765-17 x -1246315-35 x -605353-49 x -432395-85 x -249263-119 x -178045-245 x -86479-595 x -35609-833 x -25435-4165 x -5087
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 21,187,355, 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 | 21,187,355 | |
| -1 | -21,187,355 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,187,355.
Example:
1 x 21,187,355 = 21,187,355
and
-1 x -21,187,355 = 21,187,355
Notice both answers equal 21,187,355
With that explanation out of the way, let's continue. Next, we take the number 21,187,355 and divide it by 2:
21,187,355 ÷ 2 = 10,593,677.5
If the quotient is a whole number, then 2 and 10,593,677.5 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 | 21,187,355 | |
| -1 | -21,187,355 |
Now, we try dividing 21,187,355 by 3:
21,187,355 ÷ 3 = 7,062,451.6667
If the quotient is a whole number, then 3 and 7,062,451.6667 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 | 21,187,355 | |
| -1 | -21,187,355 |
Let's try dividing by 4:
21,187,355 ÷ 4 = 5,296,838.75
If the quotient is a whole number, then 4 and 5,296,838.75 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 | 21,187,355 | |
| -1 | 21,187,355 |
If you did it right, you will end up with this table:
| 1 | 5 | 7 | 17 | 35 | 49 | 85 | 119 | 245 | 595 | 833 | 4,165 | 5,087 | 25,435 | 35,609 | 86,479 | 178,045 | 249,263 | 432,395 | 605,353 | 1,246,315 | 3,026,765 | 4,237,471 | 21,187,355 |
| -1 | -5 | -7 | -17 | -35 | -49 | -85 | -119 | -245 | -595 | -833 | -4,165 | -5,087 | -25,435 | -35,609 | -86,479 | -178,045 | -249,263 | -432,395 | -605,353 | -1,246,315 | -3,026,765 | -4,237,471 | -21,187,355 |
Here are some more numbers to try:
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