Hi Saravana,
In the standard R/3 System, the item ID can be assigned as follows:
- Internally
If you do not enter an item ID, the system assigns one automatically. Internally assigned item IDs are always numeric.
- Externally
You enter an item ID that has at least one non-numeric character.
So, you cannot type a numeric number and save it.
Hope this helps
Thanks,
Prem