56640 has 56 divisors (see below), whose sum is σ = 182880. Its totient is φ = 14848.

The previous prime is 56633. The next prime is 56659. The reversal of 56640 is 4665.

It is an Ulam number.

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

56640 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 931 + ... + 989.

2⁵⁶⁶⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 56640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91440).

56640 is an abundant number, since it is smaller than the sum of its proper divisors (126240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

56640 is a wasteful number, since it uses less digits than its factorization.

56640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79 (or 69 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 56640 is about 237.9915964903. The cubic root of 56640 is about 38.4038190646.

It can be divided in two parts, 566 and 40, that added together give a palindrome (606).

The spelling of 56640 in words is "fifty-six thousand, six hundred forty".