15391054 divided by 86 
The aim is to understand the frequency of 86 in 15391054.

Let's proceed to step 1:
When dividing 1 by 86, we get 0 with a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Append the next digit (5) from the dividend to 1 and continue with: 15 / 86

Let's proceed to step 2:
15 divided by 86 is 0 with a remainder of 15.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 15 and we're left with 15.
Bring next digit (3) of the dividend behind the 15 and repeat the process: 153 / 86

Going ahead to step 3:
The number 86 fits into 153 1 times, leaving a remainder of 67.
The next digit of our result is 1. 
Result so far: 1.0
If we subtract 86 from 153, we get 67.
Fetch the next digit (9) from the dividend, attach it to 67 and continue: 679 / 86

Step 4:
If we divide 679 by 86, we get 7 and a remainder of 77.
Record the quotient 7 as the next digit in the result. 
Result so far: 17.0
If we take 602 away from 679, we end up with 77.
Grab the next digit (1) from the dividend, add it to 77, then carry on: 771 / 86

Moving on to step 5:
If we divide 771 by 86, we get 8 and a remainder of 83.
Use 8 as the next digit of our solution. 
Result so far: 178.0
If we take 688 away from 771, we end up with 83.
Append the next digit (0) from the dividend to 83 and continue with: 830 / 86

Let's proceed to step 6:
830 divided by 86 is 9 with a remainder of 56.
The number 9 becomes the next digit in our result. 
Result so far: 1789.0
Subtract 774 from 830 to get 56.
Include the next digit (5) from the dividend after 56, then repeat: 565 / 86

Let's proceed to step 7:
565 divided by 86 is 6 with a remainder of 49.
The next digit of our result is 6. 
Result so far: 17896.0
Subtracting 516 from 565 leaves us with 49.
Grab the next digit (4) from the dividend, add it to 49, then carry on: 494 / 86

Moving on to step 8:
494 divided by 86 is 5 with a remainder of 64.
Use 5 as the next digit of our solution. 
Result so far: 178965.0
If we subtract 430 from 494, we get 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Going ahead to step 9:
The number 86 fits into 640 7 times, leaving a remainder of 38.
The next digit of our result is 7. 
Result so far: 178965.7
Subtract 602 from 640 to get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Step 10:
86 goes into 380 4 times with a remainder of 36.
Use 4 as the next digit of our solution. 
Result so far: 178965.74
Subtract 344 from 380 to get 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Going ahead to step 11:
When dividing 360 by 86, we get 4 with a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 178965.744
Deduct 344 from 360 and we're left 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.

Our division results in 178965.744 with a remaining 0.0016.