86397 ÷ 7 = 12342 R3
Let's divide 86397 by 7.

Step 1:
7 goes into 8 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 7 from 8 to get 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 7

Step 2:
7 goes into 16 2 times with a remainder of 2.
Write down 2 as next digit of of the result. 
Result so far: 12
Subtract 14 from 16 to get 2.
Bring next digit (3) of the dividend behind the 2 and repeat the process: 23 / 7

Step 3:
7 goes into 23 3 times with a remainder of 2.
Write down 3 as next digit of of the result. 
Result so far: 123
Subtract 21 from 23 to get 2.
Bring next digit (9) of the dividend behind the 2 and repeat the process: 29 / 7

Step 4:
7 goes into 29 4 times with a remainder of 1.
Write down 4 as next digit of of the result. 
Result so far: 1234
Subtract 28 from 29 to get 1.
Bring next digit (7) of the dividend behind the 1 and repeat the process: 17 / 7

Step 5:
7 goes into 17 2 times with a remainder of 3.
Write down 2 as next digit of of the result. 
Result so far: 12342
Subtract 14 from 17 to get 3.

The final result is 12342 with a remainder of 3.