42444221 has 2 divisors, whose sum is σ = 42444222. Its totient is φ = 42444220.

The previous prime is 42444203. The next prime is 42444247. The reversal of 42444221 is 12244424.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37332100 + 5112121 = 6110^2 + 2261^2 .

It is a cyclic number.

It is not a de Polignac number, because 42444221 - 2¹⁰ = 42443197 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42444421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21222110 + 21222111.

It is an arithmetic number, because the mean of its divisors is an integer number (21222111).

Almost surely, 2^42444221 is an apocalyptic number.

It is an amenable number.

42444221 is a deficient number, since it is larger than the sum of its proper divisors (1).

42444221 is an equidigital number, since it uses as much as digits as its factorization.

42444221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2048, while the sum is 23.

The square root of 42444221 is about 6514.9229465896. The cubic root of 42444221 is about 348.8238644007.

Adding to 42444221 its reverse (12244424), we get a palindrome (54688645).

The spelling of 42444221 in words is "forty-two million, four hundred forty-four thousand, two hundred twenty-one".