UTN is an abbreviation that stands for "unique tax payer number". Some of the synonyms that could be used in place of UTN include Tax Identification Number (TIN), Social Security Number (SSN), Employer Identification Number (EIN), and Value Added Tax (VAT) number. These numbers are assigned by federal or state taxing authorities that track personal income and corporate profits. Having a UTN or its synonym helps individuals or businesses to comply with tax laws and maintain accurate financial records. It is important to keep track of these numbers and ensure they are up to date to avoid penalties and legal ramifications.