221212111 has 2 divisors, whose sum is σ = 221212112. Its totient is φ = 221212110.

The previous prime is 221212099. The next prime is 221212129. The reversal of 221212111 is 111212122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221212111 - 2¹³ = 221203919 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221212091 and 221212100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221212141) 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 as a sum of consecutive naturals, namely, 110606055 + 110606056.

It is an arithmetic number, because the mean of its divisors is an integer number (110606056).

Almost surely, 2^221212111 is an apocalyptic number.

221212111 is a deficient number, since it is larger than the sum of its proper divisors (1).

221212111 is an equidigital number, since it uses as much as digits as its factorization.

221212111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16, while the sum is 13.

The square root of 221212111 is about 14873.2011013097. The cubic root of 221212111 is about 604.7877232640.

Adding to 221212111 its reverse (111212122), we get a palindrome (332424233).

The spelling of 221212111 in words is "two hundred twenty-one million, two hundred twelve thousand, one hundred eleven".