219 (number)

Mathematics

• 219 is a happy number.
• Mertens function = 4, a record high.
• There are 219 partially ordered sets on four labeled elements.
• 219 is the smallest number that can be represented as a sum of four positive cubes in two different ways.
• There are 219 different space groups, discrete and full-dimensional sets of symmetries of three-dimensional space or of crystal structures.