369389 divided by 21 
We want to figure out the number of times 369389 can be divided by 21.

On to step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Take the next digit (6) from the dividend and append it to 3, then repeat: 36 / 21

On to step 2:
36 divided by 21 is 1 with a remainder of 15.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 21 from 36 to get 15.
Grab the next digit (9) from the dividend, add it to 15, then carry on: 159 / 21

Step 3:
The number 21 fits into 159 7 times, leaving a remainder of 12.
Put 7 as the next digit of the answer. 
Result so far: 17.0
If we take 147 away from 159, we end up with 12.
Take the next digit (3) from the dividend and append it to 12, then repeat: 123 / 21

Going ahead to step 4:
21 goes into 123 5 times with a remainder of 18.
The next digit of our result is 5. 
Result so far: 175.0
Subtract 105 from 123 to get 18.
Fetch the next digit (8) from the dividend, attach it to 18 and continue: 188 / 21

Step 5:
The number 21 fits into 188 8 times, leaving a remainder of 20.
Use 8 as the next digit of our solution. 
Result so far: 1758.0
If we take 168 away from 188, we end up with 20.
Bring next digit (9) of the dividend behind the 20 and repeat the process: 209 / 21

Let's proceed to step 6:
When dividing 209 by 21, we get 9 with a remainder of 20.
Put 9 as the next digit of the answer. 
Result so far: 17589.0
The remainder is 20 after subtracting 189 from 209.
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 7:
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: 17589.9
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.

Moving on to step 8:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 17589.95
Subtract 105 from 110 to 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 9:
50 divided by 21 is 2 with a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 17589.952
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.

Let's proceed to step 10:
If we divide 80 by 21, we get 3 and a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 17589.9523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 11:
If we divide 170 by 21, we get 8 and a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 17589.95238
If we subtract 168 from 170, we 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.

On to step 12:
21 goes into 20 0 times with a remainder of 20.
Write down 0 as next digit of the result. 
Result so far: 17589.95238
Subtract 0 from 20 to 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.

Moving on to step 13:
21 can be fit into 200 9 times, resulting in a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 17589.9523809
The remainder is 11 after subtracting 189 from 200.
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 14:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 17589.95238095
Subtracting 105 from 110 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

In conclusion, the division gives 17589.95238095 with a balance of 5e-09.