Let's divide 21399487 by 787
We want to figure out the number of times 21399487 can be divided by 787.

Step 1:
787 can be fit into 2 0 times, resulting in a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 787

Step 2:
787 can be fit into 21 0 times, resulting in a remainder of 21.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 21 leaves us with 21.
Bring next digit (3) of the dividend behind the 21 and repeat the process: 213 / 787

On to step 3:
213 divided by 787 is 0 with a remainder of 213.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 213 after subtracting 0 from 213.
Grab the next digit (9) from the dividend, add it to 213, then carry on: 2139 / 787

Going ahead to step 4:
787 can be fit into 2139 2 times, resulting in a remainder of 565.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
The remainder is 565 after subtracting 1574 from 2139.
Grab the next digit (9) from the dividend, add it to 565, then carry on: 5659 / 787

Advancing to step 5:
787 can be fit into 5659 7 times, resulting in a remainder of 150.
The number 7 becomes the next digit in our result. 
Result so far: 27.0
Deduct 5509 from 5659 and we're left with 150.
Bring next digit (4) of the dividend behind the 150 and repeat the process: 1504 / 787

Going ahead to step 6:
When dividing 1504 by 787, we get 1 with a remainder of 717.
Use 1 as the next digit of our solution. 
Result so far: 271.0
If we subtract 787 from 1504, we get 717.
Take the next digit (8) from the dividend and append it to 717, then repeat: 7178 / 787

On to step 7:
The number 787 fits into 7178 9 times, leaving a remainder of 95.
The number 9 becomes the next digit in our result. 
Result so far: 2719.0
If we take 7083 away from 7178, we end up with 95.
Take the next digit (7) from the dividend and append it to 95, then repeat: 957 / 787

On to step 8:
The number 787 fits into 957 1 times, leaving a remainder of 170.
The number 1 becomes the next digit in our result. 
Result so far: 27191.0
Subtracting 787 from 957 leaves us with 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1700, and continue the process.

Advancing to step 9:
787 can be fit into 1700 2 times, resulting in a remainder of 126.
The number 2 becomes the next digit in our result. 
Result so far: 27191.2
Subtracting 1574 from 1700 leaves us with 126.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1260, and continue the process.

Moving on to step 10:
787 goes into 1260 1 times with a remainder of 473.
Write down 1 as next digit of the result. 
Result so far: 27191.21
The remainder is 473 after subtracting 787 from 1260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4730, and continue the process.

Going ahead to step 11:
If we divide 4730 by 787, we get 6 and a remainder of 8.
Write down 6 as next digit of the result. 
Result so far: 27191.216
If we subtract 4722 from 4730, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 12:
787 goes into 80 0 times with a remainder of 80.
The next digit of our result is 0. 
Result so far: 27191.216
If we take 0 away from 80, we end up with 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Going ahead to step 13:
The number 787 fits into 800 1 times, leaving a remainder of 13.
Write down 1 as next digit of the result. 
Result so far: 27191.21601
Subtract 787 from 800 to get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 14:
The number 787 fits into 130 0 times, leaving a remainder of 130.
Use 0 as the next digit of our solution. 
Result so far: 27191.21601
Deduct 0 from 130 and we're left with 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Let's proceed to step 15:
When dividing 1300 by 787, we get 1 with a remainder of 513.
The next digit of our result is 1. 
Result so far: 27191.2160101
The remainder is 513 after subtracting 787 from 1300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5130, and continue the process.

Step 16:
If we divide 5130 by 787, we get 6 and a remainder of 408.
Write down 6 as next digit of the result. 
Result so far: 27191.21601016
If we take 4722 away from 5130, we end up with 408.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4080, and continue the process.

In conclusion, the division gives 27191.21601016 with a balance of 4.08e-07.