20211111211221 has 24 divisors (see below), whose sum is σ = 34178139288384. Its totient is φ = 11267518443840.

The previous prime is 20211111211163. The next prime is 20211111211223. The reversal of 20211111211221 is 12211211111202.

It is a happy number.

20211111211221 is a `hidden beast` number, since 20 + 211 + 1 + 1 + 1 + 211 + 221 = 666.

It is not a de Polignac number, because 20211111211221 - 2²⁵ = 20211077656789 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20211111211194 and 20211111211203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211111211223) 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 23 ways as a sum of consecutive naturals, for example, 3912330211 + ... + 3912335376.

It is an arithmetic number, because the mean of its divisors is an integer number (1424089137016).

Almost surely, 2^{20211111211221} is an apocalyptic number.

20211111211221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20211111211221 is a deficient number, since it is larger than the sum of its proper divisors (13967028077163).

20211111211221 is a wasteful number, since it uses less digits than its factorization.

20211111211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7824665641 (or 7824665638 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 20211111211221 its reverse (12211211111202), we get a palindrome (32422322322423).

The spelling of 20211111211221 in words is "twenty trillion, two hundred eleven billion, one hundred eleven million, two hundred eleven thousand, two hundred twenty-one".