We divide 64509859 by 15
We want to figure out the number of times 64509859 can be divided by 15.

Advancing to step 1:
15 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
Deduct 0 from 6 and we're left with 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 15

On to step 2:
When dividing 64 by 15, we get 4 with a remainder of 4.
Write down 4 as next digit of the result. 
Result so far: 4.0
Subtracting 60 from 64 leaves us with 4.
Fetch the next digit (5) from the dividend, attach it to 4 and continue: 45 / 15

On to step 3:
The number 15 fits into 45 3 times, leaving a remainder of 0.
Write down 3 as next digit of the result. 
Result so far: 43.0
Subtract 45 from 45 to get 0.
Include the next digit (0) from the dividend after 0, then repeat: 0 / 15

Step 4:
0 divided by 15 is 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 430.0
Deduct 0 from 0 and we're left with 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 15

Step 5:
When dividing 9 by 15, we get 0 with a remainder of 9.
The next digit of our result is 0. 
Result so far: 4300.0
If we take 0 away from 9, we end up with 9.
Fetch the next digit (8) from the dividend, attach it to 9 and continue: 98 / 15

Moving on to step 6:
When dividing 98 by 15, we get 6 with a remainder of 8.
The next digit of our result is 6. 
Result so far: 43006.0
If we take 90 away from 98, we end up with 8.
Append the next digit (5) from the dividend to 8 and continue with: 85 / 15

Let's proceed to step 7:
The number 15 fits into 85 5 times, leaving a remainder of 10.
Write down 5 as next digit of the result. 
Result so far: 430065.0
Deduct 75 from 85 and we're left with 10.
Include the next digit (9) from the dividend after 10, then repeat: 109 / 15

Going ahead to step 8:
When dividing 109 by 15, we get 7 with a remainder of 4.
The number 7 becomes the next digit in our result. 
Result so far: 4300657.0
Deduct 105 from 109 and we're left 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.

Moving on to step 9:
When dividing 40 by 15, we get 2 with a remainder of 10.
Use 2 as the next digit of our solution. 
Result so far: 4300657.2
Subtract 30 from 40 to 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.

Moving on to step 10:
15 goes into 100 6 times with a remainder of 10.
The next digit of our result is 6. 
Result so far: 4300657.26
If we subtract 90 from 100, 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.

On to step 11:
When dividing 100 by 15, we get 6 with a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 4300657.266
Subtracting 90 from 100 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.

The final result is 4300657.266 with a remainder of 0.001.