400419 divided by 21 
We're looking to find how many times 21 goes into 400419.

Step 1:
When dividing 4 by 21, we get 0 with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Fetch the next digit (0) from the dividend, attach it to 4 and continue: 40 / 21

Let's proceed to step 2:
40 divided by 21 is 1 with a remainder of 19.
The next digit of our result is 1. 
Result so far: 1.0
Subtracting 21 from 40 leaves us with 19.
Grab the next digit (0) from the dividend, add it to 19, then carry on: 190 / 21

Moving on to step 3:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 19.0
If we subtract 189 from 190, we get 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 21

Going ahead to step 4:
When dividing 14 by 21, we get 0 with a remainder of 14.
Record the quotient 0 as the next digit in the result. 
Result so far: 190.0
Subtracting 0 from 14 leaves us with 14.
Grab the next digit (1) from the dividend, add it to 14, then carry on: 141 / 21

Let's proceed to step 5:
When dividing 141 by 21, we get 6 with a remainder of 15.
Write down 6 as next digit of the result. 
Result so far: 1906.0
The remainder is 15 after subtracting 126 from 141.
Append the next digit (9) from the dividend to 15 and continue with: 159 / 21

Step 6:
When dividing 159 by 21, we get 7 with a remainder of 12.
The number 7 becomes the next digit in our result. 
Result so far: 19067.0
The remainder is 12 after subtracting 147 from 159.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 7:
When dividing 120 by 21, we get 5 with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 19067.5
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.

Going ahead to step 8:
21 goes into 150 7 times with a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 19067.57
The remainder is 3 after subtracting 147 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Let's proceed to step 9:
30 divided by 21 is 1 with a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 19067.571
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.

Going ahead to step 10:
21 can be fit into 90 4 times, resulting in a remainder of 6.
The next digit of our result is 4. 
Result so far: 19067.5714
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.

Advancing to step 11:
If we divide 60 by 21, we get 2 and a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 19067.57142
If we take 42 away from 60, we end up with 18.
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 12:
21 goes into 180 8 times with a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 19067.571428
If we subtract 168 from 180, we 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.

Going ahead to step 13:
The number 21 fits into 120 5 times, leaving a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 19067.5714285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 14:
21 goes into 150 7 times with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 19067.57142857
If we subtract 147 from 150, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

The quotient of the division is 19067.57142857, and the remainder is 3e-09.