212111111 has 2 divisors, whose sum is σ = 212111112. Its totient is φ = 212111110.

The previous prime is 212111101. The next prime is 212111147. The reversal of 212111111 is 111111212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212111111 is a prime.

It is a super-2 number, since 2×212111111² = 89982246819308642, which contains 22 as substring.

It is a Chen prime.

212111111 is a modest number, since divided by 11111 gives 2121 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 212111092 and 212111101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212111101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106055555 + 106055556.

It is an arithmetic number, because the mean of its divisors is an integer number (106055556).

Almost surely, 2^212111111 is an apocalyptic number.

212111111 is a deficient number, since it is larger than the sum of its proper divisors (1).

212111111 is an equidigital number, since it uses as much as digits as its factorization.

212111111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4, while the sum is 11.

The square root of 212111111 is about 14564.0348461544. The cubic root of 212111111 is about 596.3773481956.

Adding to 212111111 its reverse (111111212), we get a palindrome (323222323).

It can be divided in two parts, 21211 and 1111, that added together give a palindrome (22322).

The spelling of 212111111 in words is "two hundred twelve million, one hundred eleven thousand, one hundred eleven".