21204210239 has 2 divisors, whose sum is σ = 21204210240. Its totient is φ = 21204210238.

The previous prime is 21204210221. The next prime is 21204210241. The reversal of 21204210239 is 93201240212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21204210239 - 2¹² = 21204206143 is a prime.

Together with 21204210241, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204210259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602105119 + 10602105120.

It is an arithmetic number, because the mean of its divisors is an integer number (10602105120).

Almost surely, 2^21204210239 is an apocalyptic number.

21204210239 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204210239 is an equidigital number, since it uses as much as digits as its factorization.

21204210239 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The spelling of 21204210239 in words is "twenty-one billion, two hundred four million, two hundred ten thousand, two hundred thirty-nine".