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Eighty-one
Eighty-one
(81, LXXXI) is the
natural number
following
eighty
and preceeding
eighty-two
.
Hexadecimal
: 51
Binary
: 01010001
Factors
: 1, 3, 9, 27, 81
Factorization
:
Ordinal number
: eighty-first
81 is also:
the
atomic number
of
thallium
(Tl)
the title of a short film by Stephen Burke:
81
the model number of:
Unterseeboot 81
,
Sinclair ZX81
the
Messier number
of the
M81 Group
of galaxies
the number of the
French department
Tarn
the designation of
Interstate 81
, a freeway that runs from
Tennessee
to
New York
.
the
code for international direct dial
phone calls to
Japan
the year AD
81
or AD
1981
.