65 and preceding 67. Its ordinal form is written "sixty-sixth" or 66th.66 (sixty-six) is a positive integer following
66 is a repdigit number.
If you flip 66 upside down, it becomes 99.
In googology Edit
In Greek-based number-naming systems, 66 is associated with prefix "hexahexaconta-", and with prefix "sexasexaginti-" in Latin systems.