86391 ÷ 4 = 21597 R3
Sure thing! Let's divide 86391 by 4 together.

Step 1:
4 goes into 8 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 2
Subtract 8 from 8 to get 0.
Bring next digit (6) of the dividend behind the 0 and repeat the process: 6 / 4

Step 2:
4 goes into 6 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 21
Subtract 4 from 6 to get 2.
Bring next digit (3) of the dividend behind the 2 and repeat the process: 23 / 4

Step 3:
4 goes into 23 5 times with a remainder of 3.
Write down 5 as next digit of of the result. 
Result so far: 215
Subtract 20 from 23 to get 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 4

Step 4:
4 goes into 39 9 times with a remainder of 3.
Write down 9 as next digit of of the result. 
Result so far: 2159
Subtract 36 from 39 to get 3.
Bring next digit (1) of the dividend behind the 3 and repeat the process: 31 / 4

Step 5:
4 goes into 31 7 times with a remainder of 3.
Write down 7 as next digit of of the result. 
Result so far: 21597
Subtract 28 from 31 to get 3.

The final result is 21597 with a remainder of 3.