156 (one hundred [and] fifty-six) is the natural number, following 155 and preceding 157.
156 is an abundant number, a pronic number, a dodecagonal number, and a refactorable number.
156 is the number of graphs on 6 unlabeled nodes.
156 is a repdigit in base 5 (1111), and also in bases 25, 38, 51, 77, and 155.
156 degrees is the internal angle of a pentadecagon.