51 (fifty-one) is a positive integer following 50 and preceding 52. Its ordinal form is written "fifty-first" or 51st.

Properties Edit

51 is an odd composite number.

In googology Edit

In Greek-based number-naming systems, 51 is associated with prefix "henpentaconta-", and with prefix "unquinquaginti-" in Latin systems.

51 is the 7th output of the Xi function, \(\Xi(7) = 51\)

51 is equal to \(\text{Worm}(2)\) in Beklemishev's worms.