21232424221 has 2 divisors, whose sum is σ = 21232424222. Its totient is φ = 21232424220.

The previous prime is 21232424219. The next prime is 21232424243. The reversal of 21232424221 is 12242423212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19653236100 + 1579188121 = 140190^2 + 39739^2 .

It is a cyclic number.

It is not a de Polignac number, because 21232424221 - 2¹ = 21232424219 is a prime.

Together with 21232424219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21232424251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616212110 + 10616212111.

It is an arithmetic number, because the mean of its divisors is an integer number (10616212111).

Almost surely, 2^21232424221 is an apocalyptic number.

It is an amenable number.

21232424221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21232424221 is an equidigital number, since it uses as much as digits as its factorization.

21232424221 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21232424221 its reverse (12242423212), we get a palindrome (33474847433).

The spelling of 21232424221 in words is "twenty-one billion, two hundred thirty-two million, four hundred twenty-four thousand, two hundred twenty-one".