21211112220121 has 4 divisors (see below), whose sum is σ = 21211542454032. Its totient is φ = 21210681986212.

The previous prime is 21211112220113. The next prime is 21211112220161. The reversal of 21211112220121 is 12102221111212.

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 21211112220121 - 2³ = 21211112220113 is a prime.

It is a super-2 number, since 2×21211112220121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211112220101) 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 in 3 ways as a sum of consecutive naturals, for example, 215042995 + ... + 215141608.

It is an arithmetic number, because the mean of its divisors is an integer number (5302885613508).

Almost surely, 2^{21211112220121} is an apocalyptic number.

It is an amenable number.

21211112220121 is a deficient number, since it is larger than the sum of its proper divisors (430233911).

21211112220121 is an equidigital number, since it uses as much as digits as its factorization.

21211112220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430233910.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21211112220121 its reverse (12102221111212), we get a palindrome (33313333331333).

The spelling of 21211112220121 in words is "twenty-one trillion, two hundred eleven billion, one hundred twelve million, two hundred twenty thousand, one hundred twenty-one".