1211320111 has 16 divisors (see below), whose sum is σ = 1268847360. Its totient is φ = 1154926080.

The previous prime is 1211320079. The next prime is 1211320147. The reversal of 1211320111 is 1110231121.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1211320111 - 2⁵ = 1211320079 is a prime.

It is a super-2 number, since 2×1211320111² = 2934592822626104642, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211320091 and 1211320100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211320811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1221826 + ... + 1222816.

It is an arithmetic number, because the mean of its divisors is an integer number (79302960).

Almost surely, 2^1211320111 is an apocalyptic number.

1211320111 is a deficient number, since it is larger than the sum of its proper divisors (57527249).

1211320111 is a wasteful number, since it uses less digits than its factorization.

1211320111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1506.

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

The square root of 1211320111 is about 34804.0243506408. The cubic root of 1211320111 is about 1065.9896202292.

Adding to 1211320111 its reverse (1110231121), we get a palindrome (2321551232).

The spelling of 1211320111 in words is "one billion, two hundred eleven million, three hundred twenty thousand, one hundred eleven".