math_fact: 5406 is the number of ways a 9×1 rectangle can be surrounded by 9×1 rectangles.
trivia: 5406 is an uninteresting number.
historical_date: October 19th is the day in 1900 that Max Planck, in his house at Grunewald, on the outskirts of Berlin, discovers the law of black body emission (Planck's law).