Runtime Error: Arithmetic overflow error converting expression to data type int.

Actually the script i was testing did not have any computation nor any calculations (is there any difference?)

It was a simple cursor retriving data from temp table and updating a physical table in the database. I had declared variable to hold value from the cursor and were defined with INT datatype.

The cursor data was definitely not longer then 20 numeric characters, but i was still getting this error. Since i was in a hurry to complete the task at hand, i changed the data type to varchar(20) and proceeded.