ORA-01722 is an Oracle error, not OBIEE, but your database.
So without looking into details the message is about "invalid number" I would say you maybe have a mismatch between the Oracle database column type and the OBIEE definition in the RPD. A different type has been set by OBIEE or something around that.
Take the physical SQL and check it by hand (you are supposed to get the same error). Can also be because of data quality problems.
So first analyze what values are generating the error and then evaluate the possible solutions: fixing the source by changing the values in the db, changing the definition in OBIEE etc.
Mostly it could be because of the presentation variable. For a number column in DB your report may be passing character values or comma seperated numbers.