211221212111 has 16 divisors (see below), whose sum is σ = 275256604224. Its totient is φ = 157289485824.

The previous prime is 211221212107. The next prime is 211221212113. The reversal of 211221212111 is 111212122112.

It is a cyclic number.

It is not a de Polignac number, because 211221212111 - 2² = 211221212107 is a prime.

It is a super-2 number, since 2×211221212111² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 211221212111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221212113) 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 15 ways as a sum of consecutive naturals, for example, 68266460 + ... + 68269553.

It is an arithmetic number, because the mean of its divisors is an integer number (17203537764).

Almost surely, 2^211221212111 is an apocalyptic number.

211221212111 is a deficient number, since it is larger than the sum of its proper divisors (64035392113).

211221212111 is a wasteful number, since it uses less digits than its factorization.

211221212111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136536050.

The product of its digits is 32, while the sum is 17.

Adding to 211221212111 its reverse (111212122112), we get a palindrome (322433334223).

The spelling of 211221212111 in words is "two hundred eleven billion, two hundred twenty-one million, two hundred twelve thousand, one hundred eleven".