42243221221 has 2 divisors, whose sum is σ = 42243221222. Its totient is φ = 42243221220.

The previous prime is 42243221179. The next prime is 42243221243. The reversal of 42243221221 is 12212234224.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41814524196 + 428697025 = 204486^2 + 20705^2 .

It is a cyclic number.

It is not a de Polignac number, because 42243221221 - 2²⁵ = 42209666789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42243221621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21121610610 + 21121610611.

It is an arithmetic number, because the mean of its divisors is an integer number (21121610611).

Almost surely, 2^42243221221 is an apocalyptic number.

It is an amenable number.

42243221221 is a deficient number, since it is larger than the sum of its proper divisors (1).

42243221221 is an equidigital number, since it uses as much as digits as its factorization.

42243221221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3072, while the sum is 25.

Adding to 42243221221 its reverse (12212234224), we get a palindrome (54455455445).

The spelling of 42243221221 in words is "forty-two billion, two hundred forty-three million, two hundred twenty-one thousand, two hundred twenty-one".