2221121111981 has 2 divisors, whose sum is σ = 2221121111982. Its totient is φ = 2221121111980.

The previous prime is 2221121111933. The next prime is 2221121112113. The reversal of 2221121111981 is 1891111211222.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1813897176100 + 407223935881 = 1346810^2 + 638141^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221121111981 - 2⁶ = 2221121111917 is a prime.

It is a super-2 number, since 2×2221121111981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2221121111081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1110560555990 + 1110560555991.

It is an arithmetic number, because the mean of its divisors is an integer number (1110560555991).

Almost surely, 2^{2221121111981} is an apocalyptic number.

It is an amenable number.

2221121111981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2221121111981 is an equidigital number, since it uses as much as digits as its factorization.

2221121111981 is an odious number, because the sum of its binary digits is odd.

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

The spelling of 2221121111981 in words is "two trillion, two hundred twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, nine hundred eighty-one".