91851 ÷ 7 = 13121 R4
Let's divide 91851 by 7.

Step 1:
7 goes into 9 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 7 from 9 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 7

Step 2:
7 goes into 21 3 times with a remainder of 0.
Write down 3 as next digit of of the result. 
Result so far: 13
Subtract 21 from 21 to get 0.
Bring next digit (8) of the dividend behind the 0 and repeat the process: 8 / 7

Step 3:
7 goes into 8 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 131
Subtract 7 from 8 to get 1.
Bring next digit (5) of the dividend behind the 1 and repeat the process: 15 / 7

Step 4:
7 goes into 15 2 times with a remainder of 1.
Write down 2 as next digit of of the result. 
Result so far: 1312
Subtract 14 from 15 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 7

Step 5:
7 goes into 11 1 times with a remainder of 4.
Write down 1 as next digit of of the result. 
Result so far: 13121
Subtract 7 from 11 to get 4.

The final result is 13121 with a remainder of 4.