21724204241 has 2 divisors, whose sum is σ = 21724204242. Its totient is φ = 21724204240.

The previous prime is 21724204169. The next prime is 21724204267. The reversal of 21724204241 is 14240242712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19050900625 + 2673303616 = 138025^2 + 51704^2 .

It is a cyclic number.

It is not a de Polignac number, because 21724204241 - 2¹⁴ = 21724187857 is a prime.

It is not a weakly prime, because it can be changed into another prime (21724204741) 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, 10862102120 + 10862102121.

It is an arithmetic number, because the mean of its divisors is an integer number (10862102121).

Almost surely, 2^21724204241 is an apocalyptic number.

It is an amenable number.

21724204241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21724204241 is an equidigital number, since it uses as much as digits as its factorization.

21724204241 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7168, while the sum is 29.

Adding to 21724204241 its reverse (14240242712), we get a palindrome (35964446953).

The spelling of 21724204241 in words is "twenty-one billion, seven hundred twenty-four million, two hundred four thousand, two hundred forty-one".