55640 has 32 divisors (see below), whose sum is σ = 136080. Its totient is φ = 20352.

The previous prime is 55639. The next prime is 55661. The reversal of 55640 is 4655.

55640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 55640.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 467 + ... + 573.

2⁵⁵⁶⁴⁰ 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 55640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68040).

55640 is an abundant number, since it is smaller than the sum of its proper divisors (80440).

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

55640 is a wasteful number, since it uses less digits than its factorization.

55640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 55640 is about 235.8813260943. The cubic root of 55640 is about 38.1764645830.

The spelling of 55640 in words is "fifty-five thousand, six hundred forty".