You can lock an entire table in Numbers, but not a specific column or other range within a table. If you are worried that some of your inputs or formulas may be overwritten accidentally then you could place them in separate table(s) and lock those tables.
Keep in mind that locking a table is very “light” protection, helpful for preventing casual mistakes but not for providing industrial grade security. It is easy to simply click a locked table and unlock it.
The security for an entire document is stronger. You can assign it a password and encrypt it. Without the password it can’t be opened.
SG