Fatto matematico: 4051 is the number of partitions of 6 items into ordered lists.
Trivia: 4051 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: February 2nd is the day in 1899 that the Australian Premiers' Conference held in Melbourne decides to locate Australia's capital city, Canberra, between Sydney and Melbourne.