• 56 can be written using four 4's:

See also 113.

• 56² = 3136 is the smallest square that contains exactly two digits '3'.

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56 has 8 divisors (see below), whose sum is σ = 120. Its totient is φ = 24.

The previous prime is 53. The next prime is 59. The reversal of 56 is 65.

Added to its reverse (65) it gives a square (121 = 11²).

56 = T₁ + T₂ + ... + T₆.

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.

56 is a nontrivial binomial coefficient, being equal to C(8, 3).

It is an interprime number because it is at equal distance from previous prime (53) and next prime (59).

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.

It is a pancake number, because a pancake can be divided into 56 parts by 10 straight cuts.

It is a partition number, being equal to the number of ways a set of 11 identical objects can be partitioned into subset.

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 a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5 + ... + 11.

It is an arithmetic number, because the mean of its divisors is an integer number (15).

It is a pronic number, being equal to 7×8.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 56, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60).

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 sum of its prime factors is 13 (or 9 counting only the distinct ones).

The product of its digits is 30, while the sum is 11.

The square root of 56 is about 7.4833147735. The cubic root of 56 is about 3.8258623655.

Subtracting from 56 its sum of digits (11), we obtain a triangular number (45 = T₉).

Multiplying 56 by its sum of digits (11), we get a palindrome (616).

Adding to 56 its reverse (65), we get a palindrome (121).

The spelling of 56 in words is "fifty-six", and thus it is an aban number, an eban number, an oban number, and an uban number.