Number Gossip

(Enter a number and I'll tell you everything you wanted to know about it but were afraid to ask.)

Unique Properties of 231

  • 231 is the smallest triangular number in which the sum of the external digits equals the sum of the internal digits
  • U.S. liquid gallon is legally defined as 231 cubic inches (submitted by Ken Knowlton)

Common Properties of 231

Composite
Deficient
Evil
Lucky
Odd
Square-free
Triangular