1311161021081 has 2 divisors, whose sum is σ = 1311161021082. Its totient is φ = 1311161021080.

The previous prime is 1311161021069. The next prime is 1311161021117. The reversal of 1311161021081 is 1801201611131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 769671081481 + 541489939600 = 877309^2 + 735860^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1311161021081 is a prime.

It is a super-2 number, since 2×1311161021081² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1311161021081.

It is not a weakly prime, because it can be changed into another prime (1311161021281) 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, 655580510540 + 655580510541.

It is an arithmetic number, because the mean of its divisors is an integer number (655580510541).

Almost surely, 2^{1311161021081} is an apocalyptic number.

It is an amenable number.

1311161021081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1311161021081 is an equidigital number, since it uses as much as digits as its factorization.

1311161021081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 26.

The spelling of 1311161021081 in words is "one trillion, three hundred eleven billion, one hundred sixty-one million, twenty-one thousand, eighty-one".