55538221 has 8 divisors (see below), whose sum is σ = 57361304. Its totient is φ = 53732160.

The previous prime is 55538213. The next prime is 55538227. The reversal of 55538221 is 12283555.

It can be written as a sum of positive squares in 4 ways, for example, as 940900 + 54597321 = 970^2 + 7389^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 55538221 - 2³ = 55538213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55538227) 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, 2551 + ... + 10843.

It is an arithmetic number, because the mean of its divisors is an integer number (7170163).

Almost surely, 2^55538221 is an apocalyptic number.

It is an amenable number.

55538221 is a deficient number, since it is larger than the sum of its proper divisors (1823083).

55538221 is a wasteful number, since it uses less digits than its factorization.

55538221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8511.

The product of its digits is 12000, while the sum is 31.

The square root of 55538221 is about 7452.3969969400. The cubic root of 55538221 is about 381.5317238308.

The spelling of 55538221 in words is "fifty-five million, five hundred thirty-eight thousand, two hundred twenty-one".