- 56 is an even composite number.
- 56 is the 6th tetrahedral number.
- 56 is a friendly number.
- A Gewirtz graph has 56 nodes.
- 56 is the largest n such that nn is less than a googol.
It is also the number of possible bishop moves in 4×4 minichess.
- In Greek-based number-naming systems, 56 is associated with prefix "hexapentaconta-", and with prefix "sexquinquaginti-" in Latin systems.
- 56 is the last 2 digits of mega.
- MathWorld, Gewirtz Graph