Number field sorting

I have an ID number assigned to each lead that is assigned by Zoho on lead creation (auto number field). When I am viewing leads, how do I get this field to sort correctly? As in to sort "1" above "100" when in Ascending order. For whatever reason it ranks more digits as less than less digits (like 1000 is less than 1). Equal number of digits works (like 1-99 would be fine, but adding # 100 would place it at the top of the list). Frustrating.