1311381391 has 2 divisors, whose sum is σ = 1311381392. Its totient is φ = 1311381390.

The previous prime is 1311381371. The next prime is 1311381413. The reversal of 1311381391 is 1931831131.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1311381391 - 2¹¹ = 1311379343 is a prime.

It is a super-2 number, since 2×1311381391² = 3439442305322189762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1311381301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655690695 + 655690696.

It is an arithmetic number, because the mean of its divisors is an integer number (655690696).

Almost surely, 2^1311381391 is an apocalyptic number.

1311381391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311381391 is an equidigital number, since it uses as much as digits as its factorization.

1311381391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 31.

The square root of 1311381391 is about 36213.0003037583. Note that the first 3 decimals coincide. The cubic root of 1311381391 is about 1094.5686508806.

The spelling of 1311381391 in words is "one billion, three hundred eleven million, three hundred eighty-one thousand, three hundred ninety-one".