21545720 divided by 509 
We want to figure out the number of times 21545720 can be divided by 509.

Advancing to step 1:
The number 509 fits into 2 0 times, leaving a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Fetch the next digit (1) from the dividend, attach it to 2 and continue: 21 / 509

Let's proceed to step 2:
The number 509 fits into 21 0 times, leaving a remainder of 21.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 21, we get 21.
Bring next digit (5) of the dividend behind the 21 and repeat the process: 215 / 509

Advancing to step 3:
When dividing 215 by 509, we get 0 with a remainder of 215.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 215 leaves us with 215.
Bring next digit (4) of the dividend behind the 215 and repeat the process: 2154 / 509

On to step 4:
509 goes into 2154 4 times with a remainder of 118.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Subtract 2036 from 2154 to get 118.
Bring next digit (5) of the dividend behind the 118 and repeat the process: 1185 / 509

Let's proceed to step 5:
509 can be fit into 1185 2 times, resulting in a remainder of 167.
Record the quotient 2 as the next digit in the result. 
Result so far: 42.0
Deduct 1018 from 1185 and we're left with 167.
Append the next digit (7) from the dividend to 167 and continue with: 1677 / 509

Moving on to step 6:
509 can be fit into 1677 3 times, resulting in a remainder of 150.
Write down 3 as next digit of the result. 
Result so far: 423.0
The remainder is 150 after subtracting 1527 from 1677.
Bring next digit (2) of the dividend behind the 150 and repeat the process: 1502 / 509

On to step 7:
If we divide 1502 by 509, we get 2 and a remainder of 484.
The next digit of our result is 2. 
Result so far: 4232.0
Deduct 1018 from 1502 and we're left with 484.
Include the next digit (0) from the dividend after 484, then repeat: 4840 / 509

Let's proceed to step 8:
509 goes into 4840 9 times with a remainder of 259.
Write down 9 as next digit of the result. 
Result so far: 42329.0
Deduct 4581 from 4840 and we're left with 259.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2590, and continue the process.

Let's proceed to step 9:
509 can be fit into 2590 5 times, resulting in a remainder of 45.
Write down 5 as next digit of the result. 
Result so far: 42329.5
Subtracting 2545 from 2590 leaves us with 45.
Since there are no more digits in the dividend, we add a zero to the remainder making it 450, and continue the process.

Step 10:
509 goes into 450 0 times with a remainder of 450.
The next digit of our result is 0. 
Result so far: 42329.5
If we subtract 0 from 450, we get 450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4500, and continue the process.

Let's proceed to step 11:
If we divide 4500 by 509, we get 8 and a remainder of 428.
The next digit of our result is 8. 
Result so far: 42329.508
The remainder is 428 after subtracting 4072 from 4500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4280, and continue the process.

On to step 12:
If we divide 4280 by 509, we get 8 and a remainder of 208.
The number 8 becomes the next digit in our result. 
Result so far: 42329.5088
Subtract 4072 from 4280 to get 208.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2080, and continue the process.

Our division results in 42329.5088 with a remaining 0.00208.