21211102110021 has 4 divisors (see below), whose sum is σ = 28281469480032. Its totient is φ = 14140734740012.

The previous prime is 21211102109993. The next prime is 21211102110067. The reversal of 21211102110021 is 12001120111212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21211102110021 - 2¹⁷ = 21211101978949 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211102114021) 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 in 3 ways as a sum of consecutive naturals, for example, 3535183685001 + ... + 3535183685006.

It is an arithmetic number, because the mean of its divisors is an integer number (7070367370008).

Almost surely, 2^{21211102110021} is an apocalyptic number.

It is an amenable number.

21211102110021 is a deficient number, since it is larger than the sum of its proper divisors (7070367370011).

21211102110021 is an equidigital number, since it uses as much as digits as its factorization.

21211102110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7070367370010.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21211102110021 its reverse (12001120111212), we get a palindrome (33212222221233).

The spelling of 21211102110021 in words is "twenty-one trillion, two hundred eleven billion, one hundred two million, one hundred ten thousand, twenty-one".