2591 ÷ 6 = 431 R5
Alright, let's work through the division of 2591 by 6 step by step.

Step 1:
6 goes into 2 0 times with a remainder of 2.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 2 to get 2.
Bring next digit (5) of the dividend behind the 2 and repeat the process: 25 / 6

Step 2:
6 goes into 25 4 times with a remainder of 1.
Write down 4 as next digit of of the result. 
Result so far: 4
Subtract 24 from 25 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 6

Step 3:
6 goes into 19 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 43
Subtract 18 from 19 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 6

Step 4:
6 goes into 11 1 times with a remainder of 5.
Write down 1 as next digit of of the result. 
Result so far: 431
Subtract 6 from 11 to get 5.

The final result is 431 with a remainder of 5.