1121209999981 has 2 divisors, whose sum is σ = 1121209999982. Its totient is φ = 1121209999980.

The previous prime is 1121209999967. The next prime is 1121210000003. The reversal of 1121209999981 is 1899999021211.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1097761203081 + 23448796900 = 1047741^2 + 153130^2 .

It is an emirp because it is prime and its reverse (1899999021211) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1121209999981 - 2²³ = 1121201611373 is a prime.

It is a super-2 number, since 2×1121209999981² (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 (1121209999081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 560604999990 + 560604999991.

It is an arithmetic number, because the mean of its divisors is an integer number (560604999991).

Almost surely, 2^{1121209999981} is an apocalyptic number.

It is an amenable number.

1121209999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1121209999981 is an equidigital number, since it uses as much as digits as its factorization.

1121209999981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1889568, while the sum is 61.

The spelling of 1121209999981 in words is "one trillion, one hundred twenty-one billion, two hundred nine million, nine hundred ninety-nine thousand, nine hundred eighty-one".