Unique numbers can be referred to by a number of different terms, each of which highlights a different aspect of their distinctive nature. One synonym for unique numbers is "individual identifiers," which emphasizes their role in identifying and distinguishing one item from others. "Distinct digits" is another option, drawing attention to the digits used to create the number and the fact that they are different than those used in other unique numbers. Another synonym is "exclusive codes," which underscores the idea that each unique number represents a code that is specific to one particular item or individual. Ultimately, the choice of synonym will depend on the context and intended meaning of the term.