Hecho general: 2157 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 2157 is an unremarkable number.
Trivia: 2157 is a boring number.
Fecha histórica: November 26th is the day in 1918 that the Podgorica Assembly votes for "union of the people", declaring assimilation into the Kingdom of Serbia.