We look at the division of 21509862 by 398 
We're looking to find how many times 398 goes into 21509862.

Step 1:
If we divide 2 by 398, we get 0 and a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 398

Advancing to step 2:
The number 398 fits into 21 0 times, leaving a remainder of 21.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 21, we end up with 21.
Include the next digit (5) from the dividend after 21, then repeat: 215 / 398

On to step 3:
398 goes into 215 0 times with a remainder of 215.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 215 to get 215.
Grab the next digit (0) from the dividend, add it to 215, then carry on: 2150 / 398

Step 4:
2150 divided by 398 is 5 with a remainder of 160.
Use 5 as the next digit of our solution. 
Result so far: 5.0
Subtracting 1990 from 2150 leaves us with 160.
Grab the next digit (9) from the dividend, add it to 160, then carry on: 1609 / 398

Let's proceed to step 5:
1609 divided by 398 is 4 with a remainder of 17.
Put 4 as the next digit of the answer. 
Result so far: 54.0
If we take 1592 away from 1609, we end up with 17.
Grab the next digit (8) from the dividend, add it to 17, then carry on: 178 / 398

On to step 6:
The number 398 fits into 178 0 times, leaving a remainder of 178.
The number 0 becomes the next digit in our result. 
Result so far: 540.0
If we subtract 0 from 178, we get 178.
Append the next digit (6) from the dividend to 178 and continue with: 1786 / 398

Advancing to step 7:
1786 divided by 398 is 4 with a remainder of 194.
Put 4 as the next digit of the answer. 
Result so far: 5404.0
If we take 1592 away from 1786, we end up with 194.
Append the next digit (2) from the dividend to 194 and continue with: 1942 / 398

Advancing to step 8:
398 can be fit into 1942 4 times, resulting in a remainder of 350.
The number 4 becomes the next digit in our result. 
Result so far: 54044.0
If we take 1592 away from 1942, we end up with 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3500, and continue the process.

Moving on to step 9:
3500 divided by 398 is 8 with a remainder of 316.
The number 8 becomes the next digit in our result. 
Result so far: 54044.8
Deduct 3184 from 3500 and we're left with 316.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3160, and continue the process.

Step 10:
When dividing 3160 by 398, we get 7 with a remainder of 374.
The number 7 becomes the next digit in our result. 
Result so far: 54044.87
Subtracting 2786 from 3160 leaves us with 374.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3740, and continue the process.

On to step 11:
3740 divided by 398 is 9 with a remainder of 158.
Put 9 as the next digit of the answer. 
Result so far: 54044.879
Deduct 3582 from 3740 and we're left with 158.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1580, and continue the process.

Let's proceed to step 12:
The number 398 fits into 1580 3 times, leaving a remainder of 386.
Record the quotient 3 as the next digit in the result. 
Result so far: 54044.8793
Subtract 1194 from 1580 to get 386.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3860, and continue the process.

Going ahead to step 13:
3860 divided by 398 is 9 with a remainder of 278.
Write down 9 as next digit of the result. 
Result so far: 54044.87939
If we subtract 3582 from 3860, we get 278.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2780, and continue the process.

Advancing to step 14:
398 can be fit into 2780 6 times, resulting in a remainder of 392.
Put 6 as the next digit of the answer. 
Result so far: 54044.879396
Subtracting 2388 from 2780 leaves us with 392.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3920, and continue the process.

Step 15:
398 can be fit into 3920 9 times, resulting in a remainder of 338.
Put 9 as the next digit of the answer. 
Result so far: 54044.8793969
If we subtract 3582 from 3920, we get 338.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3380, and continue the process.

Advancing to step 16:
398 can be fit into 3380 8 times, resulting in a remainder of 196.
Write down 8 as next digit of the result. 
Result so far: 54044.87939698
Subtracting 3184 from 3380 leaves us with 196.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1960, and continue the process.

The quotient of the division is 54044.87939698, and the remainder is 1.96e-07.