Regarding the data in the column :
As previously answered, numerical data should be right aligned if their values need to be visually comparable as this aligment reveals the order relation (as opposed to an alphabetical ordering) because left-positioned zeros are implicit.
Regarding the column headers :
A column header is an indication about the content of a column. Its function is therefore different. In addition to this, its nature is different from that of the data in the column (to start with, it is generally made of words and not numbers).
For these reasons, nothing dictates that its layout should follow the same rules as that of the data in the column. The appropriate aligment rule will be based on what it is.
If your other headers are centered, centering them will feel natural and will not break your general design.
Simply put : display them just like all other headers in your table.