405449 divided by 21 
Let's see how many times 21 fits into 405449.

Advancing to step 1:
If we divide 4 by 21, we get 0 and a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Take the next digit (0) from the dividend and append it to 4, then repeat: 40 / 21

Moving on to step 2:
If we divide 40 by 21, we get 1 and a remainder of 19.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 21 from 40 leaves us with 19.
Include the next digit (5) from the dividend after 19, then repeat: 195 / 21

Advancing to step 3:
When dividing 195 by 21, we get 9 with a remainder of 6.
The next digit of our result is 9. 
Result so far: 19.0
Subtracting 189 from 195 leaves us with 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 21

Step 4:
21 can be fit into 64 3 times, resulting in a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 193.0
Subtract 63 from 64 to get 1.
Take the next digit (4) from the dividend and append it to 1, then repeat: 14 / 21

Going ahead to step 5:
If we divide 14 by 21, we get 0 and a remainder of 14.
Write down 0 as next digit of the result. 
Result so far: 1930.0
Subtracting 0 from 14 leaves us with 14.
Append the next digit (9) from the dividend to 14 and continue with: 149 / 21

Advancing to step 6:
21 goes into 149 7 times with a remainder of 2.
The number 7 becomes the next digit in our result. 
Result so far: 19307.0
Subtract 147 from 149 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 7:
The number 21 fits into 20 0 times, leaving a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 19307.0
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 8:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 19307.09
If we subtract 189 from 200, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 9:
If we divide 110 by 21, we get 5 and a remainder of 5.
The next digit of our result is 5. 
Result so far: 19307.095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 10:
21 goes into 50 2 times with a remainder of 8.
The next digit of our result is 2. 
Result so far: 19307.0952
Deduct 42 from 50 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 11:
80 divided by 21 is 3 with a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 19307.09523
If we take 63 away from 80, we end up with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 12:
21 goes into 170 8 times with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 19307.095238
Deduct 168 from 170 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 13:
20 divided by 21 is 0 with a remainder of 20.
Write down 0 as next digit of the result. 
Result so far: 19307.095238
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 14:
21 can be fit into 200 9 times, resulting in a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 19307.09523809
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

After the division, we end up with 19307.09523809 and a remainder of 1.1e-08.