Fatto matematico: 858 is the smallest palindrome with 4 different prime factors.
Trivia: 858 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: May 7th is the day in 1994 that Edvard Munch's iconic painting The Scream is recovered undamaged after having been stolen from the National Gallery of Norway in February.