In the Vinony graph
Vinony's link graph records 1 inbound reference to ۵۰۴, and connects out to list of HTTP status codes, Avro 504 and Peugeot 504.
It is catalogued under the topic Lists of ambiguous numbers.
Vinony links it to 12 Wikipedia language editions.
Available in 12 languages
via Wikidata sitelinks · CC0