No.
You can password-protect the spreadsheet (in Numbers, 'spreadsheet', 'spreadsheet document' and 'document' all refer to the entire document, which may contain several Sheets, each of which may contain several Tables).
You can lock a table, which will protect cells on that table from being selected or changed. Without selecting the cell, the user will not be able to view the formula contained in that cell. This 'locking' and 'unlocking'is a simple menu selection, and is not password controlled.
A general design principal for Numbers documents is to separate data entry and calculations, placing each type of cell as much as possible,on separate tables, allowing the calculation cells to be locked while data entry is not affected.
You can place a request for this feature using the Provide Numbers Feedback item in the Numbers menu.
Regards,
Barry