1311116221 has 4 divisors (see below), whose sum is σ = 1311213600. Its totient is φ = 1311018844.

The previous prime is 1311116203. The next prime is 1311116237. The reversal of 1311116221 is 1226111131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1226111131 = 7 ⋅175158733.

It is a cyclic number.

It is not a de Polignac number, because 1311116221 - 2⁵ = 1311116189 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 (1311116291) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24481 + ... + 56758.

It is an arithmetic number, because the mean of its divisors is an integer number (327803400).

Almost surely, 2^1311116221 is an apocalyptic number.

It is an amenable number.

1311116221 is a deficient number, since it is larger than the sum of its proper divisors (97379).

1311116221 is an equidigital number, since it uses as much as digits as its factorization.

1311116221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97378.

The product of its digits is 72, while the sum is 19.

The square root of 1311116221 is about 36209.3388644421. The cubic root of 1311116221 is about 1094.4948695646.

Adding to 1311116221 its reverse (1226111131), we get a palindrome (2537227352).

The spelling of 1311116221 in words is "one billion, three hundred eleven million, one hundred sixteen thousand, two hundred twenty-one".