1211243111 has 6 divisors (see below), whose sum is σ = 1311582960. Its totient is φ = 1118070408.

The previous prime is 1211243107. The next prime is 1211243119. The reversal of 1211243111 is 1113421121.

It is not a de Polignac number, because 1211243111 - 2² = 1211243107 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211243111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211243119) 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 5 ways as a sum of consecutive naturals, for example, 3583391 + ... + 3583728.

It is an arithmetic number, because the mean of its divisors is an integer number (218597160).

Almost surely, 2^1211243111 is an apocalyptic number.

1211243111 is a deficient number, since it is larger than the sum of its proper divisors (100339849).

1211243111 is an equidigital number, since it uses as much as digits as its factorization.

1211243111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7167145 (or 7167132 counting only the distinct ones).

The product of its digits is 48, while the sum is 17.

The square root of 1211243111 is about 34802.9181391446. The cubic root of 1211243111 is about 1065.9670324922.

Adding to 1211243111 its reverse (1113421121), we get a palindrome (2324664232).

The spelling of 1211243111 in words is "one billion, two hundred eleven million, two hundred forty-three thousand, one hundred eleven".