51821

51821 is a five-digit integer that appears in multiple, unrelated domains. In mathematics, it is an odd composite number with prime factorization 7 × 11 × 673. The digit sum is 17, indicating it is not divisible by 3 or 9, and the alternating sum of digits (5 − 1 + 8 − 2 + 1 = 11) confirms divisibility by 11.

In postal systems, 51821 is used as a United States ZIP code. ZIP codes designate geographic delivery areas, and the code 51821 identifies a specific region assigned by the United States Postal Service. The associated city and county are listed in official lookup databases.

In astronomy, 51821 is the numeric designation of a minor planet. It is the 51821st minor planet to be numbered by the Minor Planet Center, a step in the process that formally recognizes newly observed objects; many such bodies later receive official names.

Beyond these uses, the sequence 51821 may appear as a catalog, model, or serial number in various systems, including products, measurements, and datasets. As with many five-digit identifiers, its meaning is determined by the context in which it appears.