11212012111981 has 2 divisors, whose sum is σ = 11212012111982. Its totient is φ = 11212012111980.

The previous prime is 11212012111969. The next prime is 11212012112039. The reversal of 11212012111981 is 18911121021211.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8350603047081 + 2861409064900 = 2889741^2 + 1691570^2 .

It is a cyclic number.

It is not a de Polignac number, because 11212012111981 - 2²⁷ = 11211877894253 is a prime.

It is a super-2 number, since 2×11212012111981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11212012111481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5606006055990 + 5606006055991.

It is an arithmetic number, because the mean of its divisors is an integer number (5606006055991).

Almost surely, 2^{11212012111981} is an apocalyptic number.

It is an amenable number.

11212012111981 is a deficient number, since it is larger than the sum of its proper divisors (1).

11212012111981 is an equidigital number, since it uses as much as digits as its factorization.

11212012111981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 31.

The spelling of 11212012111981 in words is "eleven trillion, two hundred twelve billion, twelve million, one hundred eleven thousand, nine hundred eighty-one".