1311320111209 has 2 divisors, whose sum is σ = 1311320111210. Its totient is φ = 1311320111208.

The previous prime is 1311320111207. The next prime is 1311320111237. The reversal of 1311320111209 is 9021110231131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1140794886400 + 170525224809 = 1068080^2 + 412947^2 .

It is a cyclic number.

It is not a de Polignac number, because 1311320111209 - 2¹ = 1311320111207 is a prime.

It is a super-2 number, since 2×1311320111209² (a number of 25 digits) contains 22 as substring.

Together with 1311320111207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1311320111203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655660055604 + 655660055605.

It is an arithmetic number, because the mean of its divisors is an integer number (655660055605).

Almost surely, 2^{1311320111209} is an apocalyptic number.

It is an amenable number.

1311320111209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311320111209 is an equidigital number, since it uses as much as digits as its factorization.

1311320111209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 25.

The spelling of 1311320111209 in words is "one trillion, three hundred eleven billion, three hundred twenty million, one hundred eleven thousand, two hundred nine".