1311991824881 has 2 divisors, whose sum is σ = 1311991824882. Its totient is φ = 1311991824880.

The previous prime is 1311991824877. The next prime is 1311991824901. The reversal of 1311991824881 is 1884281991131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 703654223281 + 608337601600 = 838841^2 + 779960^2 .

It is an emirp because it is prime and its reverse (1884281991131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1311991824881 - 2² = 1311991824877 is a prime.

It is a super-3 number, since 3×1311991824881³ (a number of 37 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (1311991824581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655995912440 + 655995912441.

It is an arithmetic number, because the mean of its divisors is an integer number (655995912441).

Almost surely, 2^{1311991824881} is an apocalyptic number.

It is an amenable number.

1311991824881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311991824881 is an equidigital number, since it uses as much as digits as its factorization.

1311991824881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 56.

The spelling of 1311991824881 in words is "one trillion, three hundred eleven billion, nine hundred ninety-one million, eight hundred twenty-four thousand, eight hundred eighty-one".