1311243431 has 2 divisors, whose sum is σ = 1311243432. Its totient is φ = 1311243430.

The previous prime is 1311243413. The next prime is 1311243449. The reversal of 1311243431 is 1343421131.

Together with previous prime (1311243413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (1311243413) and next prime (1311243449).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1311243431 is a prime.

It is a super-2 number, since 2×1311243431² = 3438718670681303522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 1311243397 and 1311243406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1311243491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655621715 + 655621716.

It is an arithmetic number, because the mean of its divisors is an integer number (655621716).

Almost surely, 2^1311243431 is an apocalyptic number.

1311243431 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311243431 is an equidigital number, since it uses as much as digits as its factorization.

1311243431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 23.

The square root of 1311243431 is about 36211.0954128703. The cubic root of 1311243431 is about 1094.5302659155.

Adding to 1311243431 its reverse (1343421131), we get a palindrome (2654664562).

The spelling of 1311243431 in words is "one billion, three hundred eleven million, two hundred forty-three thousand, four hundred thirty-one".