21204240011 has 2 divisors, whose sum is σ = 21204240012. Its totient is φ = 21204240010.

The previous prime is 21204239977. The next prime is 21204240037. The reversal of 21204240011 is 11004240212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21204240011 - 2³⁴ = 4024370827 is a prime.

It is not a weakly prime, because it can be changed into another prime (21204210011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602120005 + 10602120006.

It is an arithmetic number, because the mean of its divisors is an integer number (10602120006).

Almost surely, 2^21204240011 is an apocalyptic number.

21204240011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204240011 is an equidigital number, since it uses as much as digits as its factorization.

21204240011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21204240011 its reverse (11004240212), we get a palindrome (32208480223).

The spelling of 21204240011 in words is "twenty-one billion, two hundred four million, two hundred forty thousand, eleven".