21243312241 has 4 divisors (see below), whose sum is σ = 21296288484. Its totient is φ = 21190336000.

The previous prime is 21243312131. The next prime is 21243312263. The reversal of 21243312241 is 14221334212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19208851216 + 2034461025 = 138596^2 + 45105^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243312241 - 2¹⁹ = 21242787953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21243319241) 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 in 3 ways as a sum of consecutive naturals, for example, 26487520 + ... + 26488321.

It is an arithmetic number, because the mean of its divisors is an integer number (5324072121).

Almost surely, 2^21243312241 is an apocalyptic number.

It is an amenable number.

21243312241 is a deficient number, since it is larger than the sum of its proper divisors (52976243).

21243312241 is an equidigital number, since it uses as much as digits as its factorization.

21243312241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52976242.

The product of its digits is 2304, while the sum is 25.

Adding to 21243312241 its reverse (14221334212), we get a palindrome (35464646453).

The spelling of 21243312241 in words is "twenty-one billion, two hundred forty-three million, three hundred twelve thousand, two hundred forty-one".