21164105 ÷ 409 
Let's see how many times 409 fits into 21164105.

Step 1:
409 goes into 2 0 times with 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.
Fetch the next digit (1) from the dividend, attach it to 2 and continue: 21 / 409

Step 2:
When dividing 21 by 409, we get 0 with a remainder of 21.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 21 leaves us with 21.
Take the next digit (1) from the dividend and append it to 21, then repeat: 211 / 409

Moving on to step 3:
409 can be fit into 211 0 times, resulting in a remainder of 211.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 211, we end up with 211.
Append the next digit (6) from the dividend to 211 and continue with: 2116 / 409

Step 4:
If we divide 2116 by 409, we get 5 and a remainder of 71.
Put 5 as the next digit of the answer. 
Result so far: 5.0
The remainder is 71 after subtracting 2045 from 2116.
Bring next digit (4) of the dividend behind the 71 and repeat the process: 714 / 409

Step 5:
When dividing 714 by 409, we get 1 with a remainder of 305.
Put 1 as the next digit of the answer. 
Result so far: 51.0
The remainder is 305 after subtracting 409 from 714.
Take the next digit (1) from the dividend and append it to 305, then repeat: 3051 / 409

Going ahead to step 6:
If we divide 3051 by 409, we get 7 and a remainder of 188.
Use 7 as the next digit of our solution. 
Result so far: 517.0
If we take 2863 away from 3051, we end up with 188.
Take the next digit (0) from the dividend and append it to 188, then repeat: 1880 / 409

Going ahead to step 7:
When dividing 1880 by 409, we get 4 with a remainder of 244.
Put 4 as the next digit of the answer. 
Result so far: 5174.0
Subtracting 1636 from 1880 leaves us with 244.
Fetch the next digit (5) from the dividend, attach it to 244 and continue: 2445 / 409

Moving on to step 8:
409 goes into 2445 5 times with a remainder of 400.
Write down 5 as next digit of the result. 
Result so far: 51745.0
The remainder is 400 after subtracting 2045 from 2445.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

Moving on to step 9:
4000 divided by 409 is 9 with a remainder of 319.
The next digit of our result is 9. 
Result so far: 51745.9
If we take 3681 away from 4000, we end up with 319.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3190, and continue the process.

Advancing to step 10:
409 goes into 3190 7 times with a remainder of 327.
Put 7 as the next digit of the answer. 
Result so far: 51745.97
If we take 2863 away from 3190, we end up with 327.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3270, and continue the process.

Moving on to step 11:
When dividing 3270 by 409, we get 7 with a remainder of 407.
Use 7 as the next digit of our solution. 
Result so far: 51745.977
If we subtract 2863 from 3270, we get 407.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4070, and continue the process.

Our division results in 51745.977 with a remaining 0.0407.