Fatto matematico: 2120 is the number of ways to stack 16 pennies in a line so that each penny lies on the table or on two pennies.
Trivia: 2120 is an unremarkable number.
Data storica: October 20th is the day in 1961 that the Soviet Union performs the first armed test of a submarine-launched ballistic missile, launching an R-13 from a Golf class submarine.