A:
Positive:
1 x 212404155 x 42480837 x 303434535 x 606869151 x 140665755 x 281331057 x 200954019 x 5285
Negative:
-1 x -21240415-5 x -4248083-7 x -3034345-35 x -606869-151 x -140665-755 x -28133-1057 x -20095-4019 x -5285
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 21,240,415, 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 | 21,240,415 | |
| -1 | -21,240,415 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,240,415.
Example:
1 x 21,240,415 = 21,240,415
and
-1 x -21,240,415 = 21,240,415
Notice both answers equal 21,240,415
With that explanation out of the way, let's continue. Next, we take the number 21,240,415 and divide it by 2:
21,240,415 ÷ 2 = 10,620,207.5
If the quotient is a whole number, then 2 and 10,620,207.5 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 | 21,240,415 | |
| -1 | -21,240,415 |
Now, we try dividing 21,240,415 by 3:
21,240,415 ÷ 3 = 7,080,138.3333
If the quotient is a whole number, then 3 and 7,080,138.3333 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 | 21,240,415 | |
| -1 | -21,240,415 |
Let's try dividing by 4:
21,240,415 ÷ 4 = 5,310,103.75
If the quotient is a whole number, then 4 and 5,310,103.75 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 | 21,240,415 | |
| -1 | 21,240,415 |
If you did it right, you will end up with this table:
| 1 | 5 | 7 | 35 | 151 | 755 | 1,057 | 4,019 | 5,285 | 20,095 | 28,133 | 140,665 | 606,869 | 3,034,345 | 4,248,083 | 21,240,415 |
| -1 | -5 | -7 | -35 | -151 | -755 | -1,057 | -4,019 | -5,285 | -20,095 | -28,133 | -140,665 | -606,869 | -3,034,345 | -4,248,083 | -21,240,415 |
Here are some more numbers to try:
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