55581 has 8 divisors (see below), whose sum is σ = 75264. Its totient is φ = 36480.

The previous prime is 55579. The next prime is 55589. The reversal of 55581 is 18555.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 55581 - 2¹ = 55579 is a prime.

It is a super-2 number, since 2×55581² = 6178495122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55589) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196 + ... + 386.

It is an arithmetic number, because the mean of its divisors is an integer number (9408).

2⁵⁵⁵⁸¹ is an apocalyptic number.

It is an amenable number.

55581 is a deficient number, since it is larger than the sum of its proper divisors (19683).

55581 is a wasteful number, since it uses less digits than its factorization.

55581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291.

The product of its digits is 1000, while the sum is 24.

The square root of 55581 is about 235.7562300343. The cubic root of 55581 is about 38.1629658529.

It can be divided in two parts, 555 and 81, that added together give a palindrome (636).

The spelling of 55581 in words is "fifty-five thousand, five hundred eighty-one".