55000221 has 16 divisors (see below), whose sum is σ = 74908800. Its totient is φ = 35887040.

The previous prime is 55000207. The next prime is 55000243. The reversal of 55000221 is 12200055.

It is a cyclic number.

It is not a de Polignac number, because 55000221 - 2⁵ = 55000189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 55000221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55002221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30871 + ... + 32603.

It is an arithmetic number, because the mean of its divisors is an integer number (4681800).

Almost surely, 2^55000221 is an apocalyptic number.

It is an amenable number.

55000221 is a deficient number, since it is larger than the sum of its proper divisors (19908579).

55000221 is a wasteful number, since it uses less digits than its factorization.

55000221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1956.

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

The square root of 55000221 is about 7416.2133868977. The cubic root of 55000221 is about 380.2957554406.

Adding to 55000221 its reverse (12200055), we get a palindrome (67200276).

The spelling of 55000221 in words is "fifty-five million, two hundred twenty-one", and thus it is an aban number.