Q: What are the factor combinations of the number 21,791?
A:
Positive:
1 x 217917 x 311311 x 198177 x 283
Negative:
-1 x -21791-7 x -3113-11 x -1981-77 x -283
A:
Positive:
1 x 217917 x 311311 x 198177 x 283
Negative:
-1 x -21791-7 x -3113-11 x -1981-77 x -283
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 21,791, 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 | 21,791 | |
-1 | -21,791 |
When you multiply two negative numbers together, you get a positive number. That means both the positive and negative numbers are factors of 21,791.
Example:
1 x 21,791 = 21,791
and
-1 x -21,791 = 21,791
Notice both answers equal 21,791
With that explanation out of the way, let's continue. Next, we take the number 21,791 and divide it by 2:
21,791 ÷ 2 = 10,895.5
If the quotient is a whole number, then 2 and 10,895.5 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 | 21,791 | |
-1 | -21,791 |
Now, we try dividing 21,791 by 3:
21,791 ÷ 3 = 7,263.6667
If the quotient is a whole number, then 3 and 7,263.6667 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 | 21,791 | |
-1 | -21,791 |
Let's try dividing by 4:
21,791 ÷ 4 = 5,447.75
If the quotient is a whole number, then 4 and 5,447.75 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 | 21,791 | |
-1 | 21,791 |
If you did it right, you will end up with this table:
1 | 7 | 11 | 77 | 283 | 1,981 | 3,113 | 21,791 |
-1 | -7 | -11 | -77 | -283 | -1,981 | -3,113 | -21,791 |
Here are some more numbers to try:
Try the factor calculator