646564 divided by 21 
We're looking to find how many times 21 goes into 646564.

Advancing to step 1:
21 can be fit into 6 0 times, resulting in a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 21

On to step 2:
When dividing 64 by 21, we get 3 with a remainder of 1.
The next digit of our result is 3. 
Result so far: 3.0
The remainder is 1 after subtracting 63 from 64.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 21

Let's proceed to step 3:
21 can be fit into 16 0 times, resulting in a remainder of 16.
Record the quotient 0 as the next digit in the result. 
Result so far: 30.0
Subtract 0 from 16 to get 16.
Grab the next digit (5) from the dividend, add it to 16, then carry on: 165 / 21

Going ahead to step 4:
The number 21 fits into 165 7 times, leaving a remainder of 18.
The next digit of our result is 7. 
Result so far: 307.0
The remainder is 18 after subtracting 147 from 165.
Fetch the next digit (6) from the dividend, attach it to 18 and continue: 186 / 21

Advancing to step 5:
21 can be fit into 186 8 times, resulting in a remainder of 18.
Record the quotient 8 as the next digit in the result. 
Result so far: 3078.0
The remainder is 18 after subtracting 168 from 186.
Include the next digit (4) from the dividend after 18, then repeat: 184 / 21

Let's proceed to step 6:
21 goes into 184 8 times with a remainder of 16.
Write down 8 as next digit of the result. 
Result so far: 30788.0
If we take 168 away from 184, 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.

Step 7:
The number 21 fits into 160 7 times, leaving a remainder of 13.
The next digit of our result is 7. 
Result so far: 30788.7
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.

Going ahead to step 8:
130 divided by 21 is 6 with a remainder of 4.
The next digit of our result is 6. 
Result so far: 30788.76
If we take 126 away from 130, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 9:
40 divided by 21 is 1 with a remainder of 19.
The next digit of our result is 1. 
Result so far: 30788.761
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.

Moving on to step 10:
190 divided by 21 is 9 with a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 30788.7619
Deduct 189 from 190 and we're left 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.

Moving on to step 11:
21 goes into 10 0 times with a remainder of 10.
The next digit of our result is 0. 
Result so far: 30788.7619
Subtracting 0 from 10 leaves us 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 12:
If we divide 100 by 21, we get 4 and a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 30788.761904
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.

Moving on to step 13:
When dividing 160 by 21, we get 7 with a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 30788.7619047
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.

Step 14:
130 divided by 21 is 6 with a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 30788.76190476
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.

The quotient of the division is 30788.76190476, and the remainder is 4e-09.