55221 has 8 divisors (see below), whose sum is σ = 74880. Its totient is φ = 36192.

The previous prime is 55219. The next prime is 55229. The reversal of 55221 is 12255.

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

It is not a de Polignac number, because 55221 - 2¹ = 55219 is a prime.

It is a plaindrome in base 15.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 55221.

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 55221.

It is not an unprimeable number, because it can be changed into a prime (55229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121 + ... + 353.

It is an arithmetic number, because the mean of its divisors is an integer number (9360).

2⁵⁵²²¹ is an apocalyptic number.

It is an amenable number.

55221 is a deficient number, since it is larger than the sum of its proper divisors (19659).

55221 is a wasteful number, since it uses less digits than its factorization.

55221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315.

The product of its digits is 100, while the sum is 15.

The square root of 55221 is about 234.9914892076. The cubic root of 55221 is about 38.0803930502.

Adding to 55221 its reverse (12255), we get a palindrome (67476).

It can be divided in two parts, 55 and 221, that added together give a triangular number (276 = T₂₃).

The spelling of 55221 in words is "fifty-five thousand, two hundred twenty-one".