211211111221 has 16 divisors (see below), whose sum is σ = 246381300288. Its totient is φ = 178926112000.

The previous prime is 211211111219. The next prime is 211211111249. The reversal of 211211111221 is 122111112112.

211211111221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 211211111221 - 2¹ = 211211111219 is a prime.

It is a super-2 number, since 2×211211111221² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211211111195 and 211211111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211211112221) 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 15 ways as a sum of consecutive naturals, for example, 5572555 + ... + 5610328.

It is an arithmetic number, because the mean of its divisors is an integer number (15398831268).

Almost surely, 2^211211111221 is an apocalyptic number.

It is an amenable number.

211211111221 is a deficient number, since it is larger than the sum of its proper divisors (35170189067).

211211111221 is a wasteful number, since it uses less digits than its factorization.

211211111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11183012.

The product of its digits is 16, while the sum is 16.

Adding to 211211111221 its reverse (122111112112), we get a palindrome (333322223333).

The spelling of 211211111221 in words is "two hundred eleven billion, two hundred eleven million, one hundred eleven thousand, two hundred twenty-one".