Fatto generale: 90312 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 90312 is an unremarkable number.
Trivia: 90312 is an unremarkable number.
Data storica: April 7th is the day in 529 that First draft of the Corpus Juris Civilis (a fundamental work in jurisprudence) is issued by Eastern Roman Emperor Justinian I.