21204210241 has 2 divisors, whose sum is σ = 21204210242. Its totient is φ = 21204210240.

The previous prime is 21204210239. The next prime is 21204210259. The reversal of 21204210241 is 14201240212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20305110016 + 899100225 = 142496^2 + 29985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21204210241 - 2¹ = 21204210239 is a prime.

Together with 21204210239, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21204210221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602105120 + 10602105121.

It is an arithmetic number, because the mean of its divisors is an integer number (10602105121).

Almost surely, 2^21204210241 is an apocalyptic number.

It is an amenable number.

21204210241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204210241 is an equidigital number, since it uses as much as digits as its factorization.

21204210241 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21204210241 its reverse (14201240212), we get a palindrome (35405450453).

The spelling of 21204210241 in words is "twenty-one billion, two hundred four million, two hundred ten thousand, two hundred forty-one".