3686 ÷ 4 = 921 R2
Alright, let's work through the division of 3686 by 4 step by step.

Step 1:
4 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 3 to get 3.
Bring next digit (6) of the dividend behind the 3 and repeat the process: 36 / 4

Step 2:
4 goes into 36 9 times with a remainder of 0.
Write down 9 as next digit of of the result. 
Result so far: 9
Subtract 36 from 36 to get 0.
Bring next digit (8) of the dividend behind the 0 and repeat the process: 8 / 4

Step 3:
4 goes into 8 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 92
Subtract 8 from 8 to get 0.
Bring next digit (6) of the dividend behind the 0 and repeat the process: 6 / 4

Step 4:
4 goes into 6 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 921
Subtract 4 from 6 to get 2.

The final result is 921 with a remainder of 2.