21554315 ÷ 643 
Let's see how many times 643 fits into 21554315.

Let's proceed to step 1:
2 divided by 643 is 0 with a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 643

On to step 2:
If we divide 21 by 643, we get 0 and a remainder of 21.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 21 after subtracting 0 from 21.
Bring next digit (5) of the dividend behind the 21 and repeat the process: 215 / 643

Going ahead to step 3:
215 divided by 643 is 0 with a remainder of 215.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 215 after subtracting 0 from 215.
Bring next digit (5) of the dividend behind the 215 and repeat the process: 2155 / 643

Step 4:
643 goes into 2155 3 times with a remainder of 226.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
The remainder is 226 after subtracting 1929 from 2155.
Bring next digit (4) of the dividend behind the 226 and repeat the process: 2264 / 643

Step 5:
2264 divided by 643 is 3 with a remainder of 335.
Record the quotient 3 as the next digit in the result. 
Result so far: 33.0
Deduct 1929 from 2264 and we're left with 335.
Bring next digit (3) of the dividend behind the 335 and repeat the process: 3353 / 643

Step 6:
The number 643 fits into 3353 5 times, leaving a remainder of 138.
Put 5 as the next digit of the answer. 
Result so far: 335.0
Deduct 3215 from 3353 and we're left with 138.
Include the next digit (1) from the dividend after 138, then repeat: 1381 / 643

Advancing to step 7:
When dividing 1381 by 643, we get 2 with a remainder of 95.
Record the quotient 2 as the next digit in the result. 
Result so far: 3352.0
Deduct 1286 from 1381 and we're left with 95.
Fetch the next digit (5) from the dividend, attach it to 95 and continue: 955 / 643

Going ahead to step 8:
When dividing 955 by 643, we get 1 with a remainder of 312.
The next digit of our result is 1. 
Result so far: 33521.0
Subtracting 643 from 955 leaves us with 312.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3120, and continue the process.

Let's proceed to step 9:
643 can be fit into 3120 4 times, resulting in a remainder of 548.
Use 4 as the next digit of our solution. 
Result so far: 33521.4
If we subtract 2572 from 3120, we get 548.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5480, and continue the process.

On to step 10:
643 can be fit into 5480 8 times, resulting in a remainder of 336.
The next digit of our result is 8. 
Result so far: 33521.48
If we subtract 5144 from 5480, we get 336.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3360, and continue the process.

Step 11:
3360 divided by 643 is 5 with a remainder of 145.
Write down 5 as next digit of the result. 
Result so far: 33521.485
The remainder is 145 after subtracting 3215 from 3360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1450, and continue the process.

Going ahead to step 12:
When dividing 1450 by 643, we get 2 with a remainder of 164.
Use 2 as the next digit of our solution. 
Result so far: 33521.4852
Deduct 1286 from 1450 and we're left with 164.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1640, and continue the process.

Moving on to step 13:
643 can be fit into 1640 2 times, resulting in a remainder of 354.
The next digit of our result is 2. 
Result so far: 33521.48522
Subtracting 1286 from 1640 leaves us with 354.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3540, and continue the process.

In conclusion, the division gives 33521.48522 with a balance of 0.000354.