A:
Positive:
1 x 213708555 x 427417111 x 194280555 x 388561337 x 634151153 x 185351685 x 126833707 x 5765
Negative:
-1 x -21370855-5 x -4274171-11 x -1942805-55 x -388561-337 x -63415-1153 x -18535-1685 x -12683-3707 x -5765
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 21,370,855, 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 | 21,370,855 | |
| -1 | -21,370,855 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,370,855.
Example:
1 x 21,370,855 = 21,370,855
and
-1 x -21,370,855 = 21,370,855
Notice both answers equal 21,370,855
With that explanation out of the way, let's continue. Next, we take the number 21,370,855 and divide it by 2:
21,370,855 ÷ 2 = 10,685,427.5
If the quotient is a whole number, then 2 and 10,685,427.5 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 | 21,370,855 | |
| -1 | -21,370,855 |
Now, we try dividing 21,370,855 by 3:
21,370,855 ÷ 3 = 7,123,618.3333
If the quotient is a whole number, then 3 and 7,123,618.3333 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 | 21,370,855 | |
| -1 | -21,370,855 |
Let's try dividing by 4:
21,370,855 ÷ 4 = 5,342,713.75
If the quotient is a whole number, then 4 and 5,342,713.75 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 | 21,370,855 | |
| -1 | 21,370,855 |
If you did it right, you will end up with this table:
| 1 | 5 | 11 | 55 | 337 | 1,153 | 1,685 | 3,707 | 5,765 | 12,683 | 18,535 | 63,415 | 388,561 | 1,942,805 | 4,274,171 | 21,370,855 |
| -1 | -5 | -11 | -55 | -337 | -1,153 | -1,685 | -3,707 | -5,765 | -12,683 | -18,535 | -63,415 | -388,561 | -1,942,805 | -4,274,171 | -21,370,855 |
Here are some more numbers to try:
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