21121221220211 has 32 divisors (see below), whose sum is σ = 25004991578112. Its totient is φ = 17458282939680.

The previous prime is 21121221220193. The next prime is 21121221220241. The reversal of 21121221220211 is 11202212212112.

It is a cyclic number.

It is not a de Polignac number, because 21121221220211 - 2³⁸ = 20846343313267 is a prime.

It is a super-2 number, since 2×21121221220211² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121221220241) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 73530110 + ... + 73816796.

It is an arithmetic number, because the mean of its divisors is an integer number (781405986816).

Almost surely, 2^{21121221220211} is an apocalyptic number.

21121221220211 is a deficient number, since it is larger than the sum of its proper divisors (3883770357901).

21121221220211 is a wasteful number, since it uses less digits than its factorization.

21121221220211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287919.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21121221220211 its reverse (11202212212112), we get a palindrome (32323433432323).

It can be divided in two parts, 2112122 and 1220211, that added together give a palindrome (3332333).

The spelling of 21121221220211 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred eleven".