- 65 is an odd composite number.
- 65 is the number of known idoneal numbers.
- 65 is also a semiprime number.
In Greek-based number-naming systems, 65 is associated with prefix "pentahexaconta-", and with prefix "quinsexaginti-" in Latin systems.
- OEIS, Sequence A001358. Accessed 2021-05-19.