1221211123091 has 2 divisors, whose sum is σ = 1221211123092. Its totient is φ = 1221211123090.

The previous prime is 1221211122949. The next prime is 1221211123117. The reversal of 1221211123091 is 1903211121221.

It is an a-pointer prime, because the next prime (1221211123117) can be obtained adding 1221211123091 to its sum of digits (26).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1221211123091 - 2¹⁰ = 1221211122067 is a prime.

It is a super-2 number, since 2×1221211123091² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221211123091.

It is not a weakly prime, because it can be changed into another prime (1221211129091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610605561545 + 610605561546.

It is an arithmetic number, because the mean of its divisors is an integer number (610605561546).

Almost surely, 2^{1221211123091} is an apocalyptic number.

1221211123091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221211123091 is an equidigital number, since it uses as much as digits as its factorization.

1221211123091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 26.

The spelling of 1221211123091 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, one hundred twenty-three thousand, ninety-one".