21002

21002 is a five-digit number used as an identifier in several contexts, most prominently as a United States ZIP code. As a numeric code, it appears in postal systems, catalogs, and mathematical notation.

In the U.S. Postal Service system, 21002 designates a geographic area within Maryland. ZIP codes are issued to improve mail sorting and delivery efficiency; the five-digit code is often used with the ZIP+4 extension to identify a more precise location within the broader area. The ZIP code framework supports data analysis and service planning by providing a stable geographic unit for statistics and logistics.

Beyond postal use, 21002 may appear as a model or part number in products and catalogs. In mathematics and number theory, 21002 is an even natural number between 21001 and 21003 and can be used in counting, sequencing, or labeling schemes.

As a general identifier, 21002 illustrates how five-digit sequences function across different domains: they enable organized mail delivery, systematic cataloging, and structured numerical labeling. While the primary association is with a postal code in Maryland, the number also serves as a reusable token in various non-postal contexts.