212123111 has 4 divisors (see below), whose sum is σ = 218965824. Its totient is φ = 205280400.

The previous prime is 212123083. The next prime is 212123117. The reversal of 212123111 is 111321212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212123111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212123117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3421310 + ... + 3421371.

It is an arithmetic number, because the mean of its divisors is an integer number (54741456).

Almost surely, 2^212123111 is an apocalyptic number.

212123111 is a deficient number, since it is larger than the sum of its proper divisors (6842713).

212123111 is an equidigital number, since it uses as much as digits as its factorization.

212123111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6842712.

The product of its digits is 24, while the sum is 14.

The square root of 212123111 is about 14564.4468140743. The cubic root of 212123111 is about 596.3885944920.

Adding to 212123111 its reverse (111321212), we get a palindrome (323444323).

The spelling of 212123111 in words is "two hundred twelve million, one hundred twenty-three thousand, one hundred eleven".