61 (sixty-one) is a positive integer following 60 and preceding 62. Its ordinal form is written "sixty-first" or 61st.

Properties Edit

61 is an odd prime number.

In googology Edit

In Greek-based number-naming systems, 61 is associated with prefix "henhexaconta-", and with prefix "unsexaginti-" in Latin systems.

It is one of the values of the weak Goodstein function: \(g(5)=61\).

It is equal to gag-three with the gag prefix, since A(3,3) in the Ackermann function equals 61.