55742221 has 4 divisors (see below), whose sum is σ = 55981692. Its totient is φ = 55502752.

The previous prime is 55742189. The next prime is 55742249. The reversal of 55742221 is 12224755.

55742221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12224755 = 5 ⋅2444951.

It can be written as a sum of positive squares in 2 ways, for example, as 18361225 + 37380996 = 4285^2 + 6114^2 .

It is a cyclic number.

It is not a de Polignac number, because 55742221 - 2⁵ = 55742189 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55742221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55746221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119386 + ... + 119851.

It is an arithmetic number, because the mean of its divisors is an integer number (13995423).

Almost surely, 2^55742221 is an apocalyptic number.

It is an amenable number.

55742221 is a deficient number, since it is larger than the sum of its proper divisors (239471).

55742221 is a wasteful number, since it uses less digits than its factorization.

55742221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239470.

The product of its digits is 5600, while the sum is 28.

The square root of 55742221 is about 7466.0713229918. The cubic root of 55742221 is about 381.9982936247.

Adding to 55742221 its reverse (12224755), we get a palindrome (67966976).

It can be divided in two parts, 557 and 42221, that added together give a triangular number (42778 = T₂₉₂).

The spelling of 55742221 in words is "fifty-five million, seven hundred forty-two thousand, two hundred twenty-one".