It is a Jordan-Polya number, since it can be written as (2!)6.
64 is nontrivially palindromic in base 7 and base 15.
64 is an esthetic number in base 3, base 7 and base 12, because in such bases it adjacent digits differ by 1.
It is an ABA number since it can be written as A⋅BA, here for A=4, B=2.
It is a Duffinian number.
64 is an undulating number in base 7.
64 is a nontrivial repdigit in base 15.
It is a plaindrome in base 5, base 6, base 11, base 13, base 14 and base 15.
It is a nialpdrome in base 2, base 4, base 8, base 9, base 10, base 12, base 15 and base 16.
It is a zygodrome in base 15.
It is a self number, because there is not a number n which added to its sum of digits gives 64.
It is an upside-down number.
In principle, a polygon with 64 sides can be constructed with ruler and compass.
It is an impolite number, since it cannot be written as a nontrivial sum of consecutive naturals.
64 is the 8-th square number.
64 is the 7-th centered triangular number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 64
64 is an equidigital number, since it uses as much as digits as its factorization.
64 is an odious number, because the sum of its binary digits is odd.