231211111 has 4 divisors (see below), whose sum is σ = 241263792. Its totient is φ = 221158432.

The previous prime is 231211109. The next prime is 231211153. The reversal of 231211111 is 111112132.

It is a happy number.

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

It is not a de Polignac number, because 231211111 - 2¹ = 231211109 is a prime.

It is a Duffinian number.

231211111 is a modest number, since divided by 11111 gives 2312 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 231211091 and 231211100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231214111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5026306 + ... + 5026351.

It is an arithmetic number, because the mean of its divisors is an integer number (60315948).

Almost surely, 2^231211111 is an apocalyptic number.

231211111 is a deficient number, since it is larger than the sum of its proper divisors (10052681).

231211111 is a wasteful number, since it uses less digits than its factorization.

231211111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10052680.

The product of its digits is 12, while the sum is 13.

The square root of 231211111 is about 15205.6276095398. The cubic root of 231211111 is about 613.7661038329.

Adding to 231211111 its reverse (111112132), we get a palindrome (342323243).

The spelling of 231211111 in words is "two hundred thirty-one million, two hundred eleven thousand, one hundred eleven".