21123131230211 has 2 divisors, whose sum is σ = 21123131230212. Its totient is φ = 21123131230210.

The previous prime is 21123131230199. The next prime is 21123131230219. The reversal of 21123131230211 is 11203213132112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123131230211 is a prime.

It is not a weakly prime, because it can be changed into another prime (21123131230219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561565615105 + 10561565615106.

It is an arithmetic number, because the mean of its divisors is an integer number (10561565615106).

Almost surely, 2^{21123131230211} is an apocalyptic number.

21123131230211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123131230211 is an equidigital number, since it uses as much as digits as its factorization.

21123131230211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

Adding to 21123131230211 its reverse (11203213132112), we get a palindrome (32326344362323).

The spelling of 21123131230211 in words is "twenty-one trillion, one hundred twenty-three billion, one hundred thirty-one million, two hundred thirty thousand, two hundred eleven".