A:
Positive:
1 x 2121039713 x 163156929 x 731393127 x 167011377 x 56261443 x 478791651 x 128473683 x 5759
Negative:
-1 x -21210397-13 x -1631569-29 x -731393-127 x -167011-377 x -56261-443 x -47879-1651 x -12847-3683 x -5759
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 21,210,397, 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 | 21,210,397 | |
| -1 | -21,210,397 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,210,397.
Example:
1 x 21,210,397 = 21,210,397
and
-1 x -21,210,397 = 21,210,397
Notice both answers equal 21,210,397
With that explanation out of the way, let's continue. Next, we take the number 21,210,397 and divide it by 2:
21,210,397 ÷ 2 = 10,605,198.5
If the quotient is a whole number, then 2 and 10,605,198.5 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 | 21,210,397 | |
| -1 | -21,210,397 |
Now, we try dividing 21,210,397 by 3:
21,210,397 ÷ 3 = 7,070,132.3333
If the quotient is a whole number, then 3 and 7,070,132.3333 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 | 21,210,397 | |
| -1 | -21,210,397 |
Let's try dividing by 4:
21,210,397 ÷ 4 = 5,302,599.25
If the quotient is a whole number, then 4 and 5,302,599.25 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 | 21,210,397 | |
| -1 | 21,210,397 |
If you did it right, you will end up with this table:
| 1 | 13 | 29 | 127 | 377 | 443 | 1,651 | 3,683 | 5,759 | 12,847 | 47,879 | 56,261 | 167,011 | 731,393 | 1,631,569 | 21,210,397 |
| -1 | -13 | -29 | -127 | -377 | -443 | -1,651 | -3,683 | -5,759 | -12,847 | -47,879 | -56,261 | -167,011 | -731,393 | -1,631,569 | -21,210,397 |
Here are some more numbers to try:
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