405654 ÷ 21 
We're looking to find how many times 21 goes into 405654.

Going ahead to step 1:
4 divided by 21 is 0 with a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Bring next digit (0) of the dividend behind the 4 and repeat the process: 40 / 21

Let's proceed to step 2:
The number 21 fits into 40 1 times, leaving a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 21 from 40, we get 19.
Take the next digit (5) from the dividend and append it to 19, then repeat: 195 / 21

Advancing to step 3:
21 can be fit into 195 9 times, resulting in a remainder of 6.
Use 9 as the next digit of our solution. 
Result so far: 19.0
The remainder is 6 after subtracting 189 from 195.
Fetch the next digit (6) from the dividend, attach it to 6 and continue: 66 / 21

Let's proceed to step 4:
21 goes into 66 3 times with a remainder of 3.
Write down 3 as next digit of the result. 
Result so far: 193.0
The remainder is 3 after subtracting 63 from 66.
Include the next digit (5) from the dividend after 3, then repeat: 35 / 21

Moving on to step 5:
21 goes into 35 1 times with a remainder of 14.
Write down 1 as next digit of the result. 
Result so far: 1931.0
Subtract 21 from 35 to get 14.
Take the next digit (4) from the dividend and append it to 14, then repeat: 144 / 21

Moving on to step 6:
The number 21 fits into 144 6 times, leaving a remainder of 18.
Record the quotient 6 as the next digit in the result. 
Result so far: 19316.0
The remainder is 18 after subtracting 126 from 144.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 7:
When dividing 180 by 21, we get 8 with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 19316.8
Subtracting 168 from 180 leaves us with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 8:
The number 21 fits into 120 5 times, leaving a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 19316.85
Deduct 105 from 120 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 9:
When dividing 150 by 21, we get 7 with a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 19316.857
Subtracting 147 from 150 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 10:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 19316.8571
Subtract 21 from 30 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 11:
21 goes into 90 4 times with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 19316.85714
Subtract 84 from 90 to 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.

On to step 12:
If we divide 60 by 21, we get 2 and a remainder of 18.
The next digit of our result is 2. 
Result so far: 19316.857142
The remainder is 18 after subtracting 42 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 13:
180 divided by 21 is 8 with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 19316.8571428
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 14:
120 divided by 21 is 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 19316.85714285
If we subtract 105 from 120, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

The final result is 19316.85714285 with a remainder of 1.5e-08.