81

81 (eighty-one) is a positive integer following 80 and preceding 82. Its ordinal form is written "eighty-first" or 81st.
== Properties ==
*81 is an OEIS, Sequence A002808 (accessed 2021-02-07).
*81 is the 9th squared number.
*81 is the only number that is the square of the sum of its digits.
== In googology ==
*In Greek-based number-naming systems, 81 is associated with prefix "henoctaconta-", and with prefix "unoctoginti-" in Latin systems.
*It can be named "garnine" with the gar- prefix.
==Sources==
Category:Numbers
Category:Class 1
Category:Numbers 0-99
Category:Numbers with 1 to 2 digits
Category:Powers of 3