1211200120981 has 2 divisors, whose sum is σ = 1211200120982. Its totient is φ = 1211200120980.

The previous prime is 1211200120957. The next prime is 1211200121011. The reversal of 1211200120981 is 1890210021121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1188882748881 + 22317372100 = 1090359^2 + 149390^2 .

It is an emirp because it is prime and its reverse (1890210021121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211200120981 - 2³⁷ = 1073761167509 is a prime.

It is a super-2 number, since 2×1211200120981² (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 (1211200120951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605600060490 + 605600060491.

It is an arithmetic number, because the mean of its divisors is an integer number (605600060491).

Almost surely, 2^{1211200120981} is an apocalyptic number.

It is an amenable number.

1211200120981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211200120981 is an equidigital number, since it uses as much as digits as its factorization.

1211200120981 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 28.

The spelling of 1211200120981 in words is "one trillion, two hundred eleven billion, two hundred million, one hundred twenty thousand, nine hundred eighty-one".