• 562 = 3136 is the smallest square that contains exactly two digits '3'.
Subtracting from 56 its sum of digits (11), we obtain a triangular number (45 = T9).
Multipling 56 by its sum of digits (11), we get a palindrome (616).
Adding to 56 its reverse (65), we get a palindrome (121).
56 is nontrivially palindromic in base 3 and base 13.
56 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
56 is an esthetic number in base 10, 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 (8).
56 is an admirable number.
It is a tetranacci number.
It is a magnanimous number.
It is an alternating number because its digits alternate between odd and even.
56 is a nontrivial repdigit in base 13.
It is a plaindrome in base 10, base 12, base 13, base 15 and base 16.
It is a nialpdrome in base 2, base 4, base 5, base 7, base 8, base 9, base 11, base 13 and base 14.
It is a zygodrome in base 2 and base 13.
It is a congruent number.
It is the 6-th tetrahedral number.
It is an amenable number.
56 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
56 is a wasteful number, since it uses less digits than its factorization.
56 is an odious number, because the sum of its binary digits is odd.
The square root of 56 is about 7.4833147735. The cubic root of 56 is about 3.8258623655.