111222211001981 has 2 divisors, whose sum is σ = 111222211001982. Its totient is φ = 111222211001980.

The previous prime is 111222211001971. The next prime is 111222211002011. The reversal of 111222211001981 is 189100112222111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71660186674756 + 39562024327225 = 8465234^2 + 6289835^2 .

It is a cyclic number.

It is not a de Polignac number, because 111222211001981 - 2¹⁸ = 111222210739837 is a prime.

It is a super-4 number, since 4×111222211001981⁴ (a number of 57 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111222211001971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55611105500990 + 55611105500991.

It is an arithmetic number, because the mean of its divisors is an integer number (55611105500991).

Almost surely, 2^{111222211001981} is an apocalyptic number.

It is an amenable number.

111222211001981 is a deficient number, since it is larger than the sum of its proper divisors (1).

111222211001981 is an equidigital number, since it uses as much as digits as its factorization.

111222211001981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 32.

The spelling of 111222211001981 in words is "one hundred eleven trillion, two hundred twenty-two billion, two hundred eleven million, one thousand, nine hundred eighty-one".