1664 is an esthetic number in base 7, 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 (16).
It is a plaindrome in base 9.
It is a nialpdrome in base 8.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 1664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1785).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1664 is an equidigital number, since it uses as much as digits as its factorization.
1664 is an odious number, because the sum of its binary digits is odd.
The square root of 1664 is about 40.7921561087. The cubic root of 1664 is about 11.8499842736.
Adding to 1664 its sum of digits (17), we get a square (1681 = 412).
The spelling of 1664 in words is "one thousand, six hundred sixty-four".