general_fact: 16 is the number of personality types in the Myers-Briggs classification system.
math_fact: 16 is the only number of the form x^{y} = y^{x} with x and y being different integers.
trivia: 16 is the number of personality types in the Myers-Briggs classification system.
historical_date: January 16th is the day in 1605 that the first edition of El ingenioso hidalgo Don Quijote de la Mancha (Book One of Don Quixote) by Miguel de Cervantes is published in Madrid, Spain.