1221012231191 has 2 divisors, whose sum is σ = 1221012231192. Its totient is φ = 1221012231190.

The previous prime is 1221012231163. The next prime is 1221012231209. The reversal of 1221012231191 is 1911322101221.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221012231191 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221012231191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221012231121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610506115595 + 610506115596.

It is an arithmetic number, because the mean of its divisors is an integer number (610506115596).

Almost surely, 2^{1221012231191} is an apocalyptic number.

1221012231191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221012231191 is an equidigital number, since it uses as much as digits as its factorization.

1221012231191 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 1221012231191 in words is "one trillion, two hundred twenty-one billion, twelve million, two hundred thirty-one thousand, one hundred ninety-one".