422

422 is a natural number that follows 421 and precedes 423. In mathematics, it is an even composite number. Its prime factorization is 2 × 211, with 211 being a prime number.

In decimal notation, 422 is a three-digit number and is not a palindrome, since it reads 422 forward and 224 backward. In Roman numerals, 422 is written as CDXXII.

As a calendar year, 422 CE is a point in late antiquity. Years labeled 422 CE appear in historical timelines of the late Roman Empire and surrounding regions, though the specific events of that year vary by source.

In computing, 422 is an HTTP status code meaning Unprocessable Entity. It is defined in the WebDAV extension to HTTP (RFC 4918) and is used when the server understands the content type and syntax of the request but cannot process it due to semantic errors, such as failed validations. It is commonly encountered in web APIs and services when input data fails business rules or constraints.

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