12121111 has 4 divisors (see below), whose sum is σ = 12241224. Its totient is φ = 12001000.

The previous prime is 12121103. The next prime is 12121121. The reversal of 12121111 is 11112121.

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

It is a cyclic number.

It is not a de Polignac number, because 12121111 - 2³ = 12121103 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 (12121121) 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 in 3 ways as a sum of consecutive naturals, for example, 59905 + ... + 60106.

It is an arithmetic number, because the mean of its divisors is an integer number (3060306).

Almost surely, 2^12121111 is an apocalyptic number.

12121111 is a deficient number, since it is larger than the sum of its proper divisors (120113).

12121111 is a wasteful number, since it uses less digits than its factorization.

12121111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120112.

The product of its digits is 4, while the sum is 10.

The square root of 12121111 is about 3481.5385966552. The cubic root of 12121111 is about 229.7104800708.

Adding to 12121111 its reverse (11112121), we get a palindrome (23233232).

It can be divided in two parts, 12121 and 111, that multiplied together give a palindrome (1345431).

The spelling of 12121111 in words is "twelve million, one hundred twenty-one thousand, one hundred eleven".