1311221111 has 2 divisors, whose sum is σ = 1311221112. Its totient is φ = 1311221110.

The previous prime is 1311221077. The next prime is 1311221143. The reversal of 1311221111 is 1111221131.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1311221111 - 2³⁰ = 237479287 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1311221411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655610555 + 655610556.

It is an arithmetic number, because the mean of its divisors is an integer number (655610556).

Almost surely, 2^1311221111 is an apocalyptic number.

1311221111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311221111 is an equidigital number, since it uses as much as digits as its factorization.

1311221111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12, while the sum is 14.

The square root of 1311221111 is about 36210.7872187281. The cubic root of 1311221111 is about 1094.5240555116.

Adding to 1311221111 its reverse (1111221131), we get a palindrome (2422442242).

The spelling of 1311221111 in words is "one billion, three hundred eleven million, two hundred twenty-one thousand, one hundred eleven".