1211121099161 has 2 divisors, whose sum is σ = 1211121099162. Its totient is φ = 1211121099160.

The previous prime is 1211121099131. The next prime is 1211121099191. The reversal of 1211121099161 is 1619901211121.

It is a balanced prime because it is at equal distance from previous prime (1211121099131) and next prime (1211121099191).

It can be written as a sum of positive squares in only one way, i.e., 761491843225 + 449629255936 = 872635^2 + 670544^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211121099161 - 2¹⁰ = 1211121098137 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211121099131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605560549580 + 605560549581.

It is an arithmetic number, because the mean of its divisors is an integer number (605560549581).

Almost surely, 2^{1211121099161} is an apocalyptic number.

It is an amenable number.

1211121099161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211121099161 is an equidigital number, since it uses as much as digits as its factorization.

1211121099161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 35.

The spelling of 1211121099161 in words is "one trillion, two hundred eleven billion, one hundred twenty-one million, ninety-nine thousand, one hundred sixty-one".