• 80 can be written using four 4's:
• Deleting all the even digits from 280 = 1208925819614629174706176 we obtain a prime (195191917717).
80 is nontrivially palindromic in base 3, base 6, base 9 and base 15.
80 is an esthetic number in base 6, because in such base its adjacent digits differ by 1.
It is a tau number, because it is divible by the number of its divisors (10).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
80 is an undulating number in base 6.
80 is a nontrivial repdigit in base 3, base 9 and base 15.
It is a plaindrome in base 3, base 9, base 12, base 14 and base 15.
It is a nialpdrome in base 3, base 4, base 5, base 9, base 10, base 11, base 13, base 15 and base 16.
It is a zygodrome in base 3, base 4, base 9 and base 15.
It is a congruent number.
Being equal to 3×33-1, it is a generalized Woodall number.
In principle, a polygon with 80 sides can be constructed with ruler and compass.
It is an amenable number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
80 is a wasteful number, since it uses less digits than its factorization.
80 is an evil number, because the sum of its binary digits is even.
The square root of 80 is about 8.9442719100. The cubic root of 80 is about 4.3088693801.