Fatto generale: 4843 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 4843 is a value of n for which s(f(n)) = 2s(n).
Trivia: 4843 is an uninteresting number.
Data storica: April 4th is the day in 1994 that Marc Andreessen and Jim Clark found Netscape Communications Corporation under the name "Mosaic Communications Corporation".