81861 ÷ 1 = 81861 R0
Alright, let's work through the division of 81861 by 1 step by step.

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

Step 2:
1 goes into 1 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 81
Subtract 1 from 1 to get 0.
Bring next digit (8) of the dividend behind the 0 and repeat the process: 8 / 1

Step 3:
1 goes into 8 8 times with a remainder of 0.
Write down 8 as next digit of of the result. 
Result so far: 818
Subtract 8 from 8 to get 0.
Bring next digit (6) of the dividend behind the 0 and repeat the process: 6 / 1

Step 4:
1 goes into 6 6 times with a remainder of 0.
Write down 6 as next digit of of the result. 
Result so far: 8186
Subtract 6 from 6 to get 0.
Bring next digit (1) of the dividend behind the 0 and repeat the process: 1 / 1

Step 5:
1 goes into 1 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 81861
Subtract 1 from 1 to get 0.

The final result is 81861 with a remainder of 0.