Fatto generale: 8406 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 8406 is the number of ways to divide 8 black and 8 white beads into piles.
Trivia: 8406 is an uninteresting number.
Data storica: January 5th is the day in 1993 that the oil tanker MV Braer runs aground on the coast of the Shetland Islands, spilling 84,700 tons of crude oil.