858553 ÷ 21 
Let's see how many times 21 fits into 858553.

On to step 1:
When dividing 8 by 21, we get 0 with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Append the next digit (5) from the dividend to 8 and continue with: 85 / 21

Let's proceed to step 2:
When dividing 85 by 21, we get 4 with a remainder of 1.
Use 4 as the next digit of our solution. 
Result so far: 4.0
Subtract 84 from 85 to get 1.
Grab the next digit (8) from the dividend, add it to 1, then carry on: 18 / 21

Advancing to step 3:
21 goes into 18 0 times with a remainder of 18.
Write down 0 as next digit of the result. 
Result so far: 40.0
The remainder is 18 after subtracting 0 from 18.
Grab the next digit (5) from the dividend, add it to 18, then carry on: 185 / 21

Let's proceed to step 4:
If we divide 185 by 21, we get 8 and a remainder of 17.
The next digit of our result is 8. 
Result so far: 408.0
The remainder is 17 after subtracting 168 from 185.
Include the next digit (5) from the dividend after 17, then repeat: 175 / 21

On to step 5:
175 divided by 21 is 8 with a remainder of 7.
The number 8 becomes the next digit in our result. 
Result so far: 4088.0
Subtract 168 from 175 to get 7.
Append the next digit (3) from the dividend to 7 and continue with: 73 / 21

Step 6:
When dividing 73 by 21, we get 3 with a remainder of 10.
The number 3 becomes the next digit in our result. 
Result so far: 40883.0
Deduct 63 from 73 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 7:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 40883.4
Deduct 84 from 100 and we're left with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 8:
The number 21 fits into 160 7 times, leaving a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 40883.47
Deduct 147 from 160 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 9:
21 goes into 130 6 times with a remainder of 4.
The next digit of our result is 6. 
Result so far: 40883.476
If we subtract 126 from 130, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 10:
When dividing 40 by 21, we get 1 with a remainder of 19.
Write down 1 as next digit of the result. 
Result so far: 40883.4761
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 11:
If we divide 190 by 21, we get 9 and a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 40883.47619
If we take 189 away from 190, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 12:
21 goes into 10 0 times with a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 40883.47619
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 13:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 40883.4761904
The remainder is 16 after subtracting 84 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 14:
If we divide 160 by 21, we get 7 and a remainder of 13.
The next digit of our result is 7. 
Result so far: 40883.47619047
The remainder is 13 after subtracting 147 from 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The quotient of the division is 40883.47619047, and the remainder is 1.3e-08.