63871221 ÷ 15 
Our goal is to divide 63871221 by 15.

On to step 1:
6 divided by 15 is 0 with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Fetch the next digit (3) from the dividend, attach it to 6 and continue: 63 / 15

Let's proceed to step 2:
When dividing 63 by 15, we get 4 with a remainder of 3.
Write down 4 as next digit of the result. 
Result so far: 4.0
The remainder is 3 after subtracting 60 from 63.
Bring next digit (8) of the dividend behind the 3 and repeat the process: 38 / 15

Going ahead to step 3:
The number 15 fits into 38 2 times, leaving a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 42.0
The remainder is 8 after subtracting 30 from 38.
Append the next digit (7) from the dividend to 8 and continue with: 87 / 15

Moving on to step 4:
The number 15 fits into 87 5 times, leaving a remainder of 12.
The next digit of our result is 5. 
Result so far: 425.0
The remainder is 12 after subtracting 75 from 87.
Grab the next digit (1) from the dividend, add it to 12, then carry on: 121 / 15

Step 5:
The number 15 fits into 121 8 times, leaving a remainder of 1.
Record the quotient 8 as the next digit in the result. 
Result so far: 4258.0
Subtracting 120 from 121 leaves us with 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 15

On to step 6:
When dividing 12 by 15, we get 0 with a remainder of 12.
The number 0 becomes the next digit in our result. 
Result so far: 42580.0
If we take 0 away from 12, we end up with 12.
Fetch the next digit (2) from the dividend, attach it to 12 and continue: 122 / 15

Advancing to step 7:
15 can be fit into 122 8 times, resulting in a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 425808.0
The remainder is 2 after subtracting 120 from 122.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 15

On to step 8:
21 divided by 15 is 1 with a remainder of 6.
Use 1 as the next digit of our solution. 
Result so far: 4258081.0
If we subtract 15 from 21, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 9:
When dividing 60 by 15, we get 4 with a remainder of 0.
The number 4 becomes the next digit in our result. 
Result so far: 4258081.4
Subtracting 60 from 60 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 10:
The number 15 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 4258081.4
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 11:
If we divide 0 by 15, we get 0 and a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 4258081.4
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

In conclusion, the division gives 4258081.4 with a balance of 0.0.