111000011981 has 2 divisors, whose sum is σ = 111000011982. Its totient is φ = 111000011980.

The previous prime is 111000011977. The next prime is 111000011987. The reversal of 111000011981 is 189110000111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57238170025 + 53761841956 = 239245^2 + 231866^2 .

It is a cyclic number.

It is not a de Polignac number, because 111000011981 - 2² = 111000011977 is a prime.

It is a super-2 number, since 2×111000011981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111000011987) 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, 55500005990 + 55500005991.

It is an arithmetic number, because the mean of its divisors is an integer number (55500005991).

Almost surely, 2^111000011981 is an apocalyptic number.

It is an amenable number.

111000011981 is a deficient number, since it is larger than the sum of its proper divisors (1).

111000011981 is an equidigital number, since it uses as much as digits as its factorization.

111000011981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 23.

The spelling of 111000011981 in words is "one hundred eleven billion, eleven thousand, nine hundred eighty-one".