11111111109881 has 2 divisors, whose sum is σ = 11111111109882. Its totient is φ = 11111111109880.

The previous prime is 11111111109863. The next prime is 11111111109911. The reversal of 11111111109881 is 18890111111111.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10731520810000 + 379590299881 = 3275900^2 + 616109^2 .

It is a cyclic number.

It is not a de Polignac number, because 11111111109881 - 2¹⁴ = 11111111093497 is a prime.

It is a super-3 number, since 3×11111111109881³ (a number of 40 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 (11111111109481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5555555554940 + 5555555554941.

It is an arithmetic number, because the mean of its divisors is an integer number (5555555554941).

Almost surely, 2^{11111111109881} is an apocalyptic number.

It is an amenable number.

11111111109881 is a deficient number, since it is larger than the sum of its proper divisors (1).

11111111109881 is an equidigital number, since it uses as much as digits as its factorization.

11111111109881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 35.

The spelling of 11111111109881 in words is "eleven trillion, one hundred eleven billion, one hundred eleven million, one hundred nine thousand, eight hundred eighty-one".