720553 divided by 21 
Let's see how many times 21 fits into 720553.

Step 1:
When dividing 7 by 21, we get 0 with a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Take the next digit (2) from the dividend and append it to 7, then repeat: 72 / 21

Going ahead to step 2:
When dividing 72 by 21, we get 3 with a remainder of 9.
Write down 3 as next digit of the result. 
Result so far: 3.0
If we take 63 away from 72, we end up with 9.
Grab the next digit (0) from the dividend, add it to 9, then carry on: 90 / 21

On to step 3:
90 divided by 21 is 4 with a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 34.0
The remainder is 6 after subtracting 84 from 90.
Fetch the next digit (5) from the dividend, attach it to 6 and continue: 65 / 21

Going ahead to step 4:
The number 21 fits into 65 3 times, leaving a remainder of 2.
The next digit of our result is 3. 
Result so far: 343.0
If we take 63 away from 65, we end up with 2.
Grab the next digit (5) from the dividend, add it to 2, then carry on: 25 / 21

Moving on to step 5:
The number 21 fits into 25 1 times, leaving a remainder of 4.
Put 1 as the next digit of the answer. 
Result so far: 3431.0
Deduct 21 from 25 and we're left with 4.
Take the next digit (3) from the dividend and append it to 4, then repeat: 43 / 21

Let's proceed to step 6:
43 divided by 21 is 2 with a remainder of 1.
Write down 2 as next digit of the result. 
Result so far: 34312.0
If we subtract 42 from 43, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 7:
When dividing 10 by 21, we get 0 with a remainder of 10.
The next digit of our result is 0. 
Result so far: 34312.0
If we take 0 away from 10, we end up 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.

Let's proceed to step 8:
21 goes into 100 4 times with a remainder of 16.
The next digit of our result is 4. 
Result so far: 34312.04
If we take 84 away from 100, we end up 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.

On to step 9:
When dividing 160 by 21, we get 7 with a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 34312.047
If we take 147 away from 160, we end up 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.

Let's proceed to step 10:
21 goes into 130 6 times with a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 34312.0476
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.

Step 11:
The number 21 fits into 40 1 times, leaving a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 34312.04761
Deduct 21 from 40 and we're left 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.

Moving on to step 12:
21 goes into 190 9 times with a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 34312.047619
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 13:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 34312.047619
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 14:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 34312.04761904
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.

After the division, we end up with 34312.04761904 and a remainder of 1.6e-08.