1221001123291 has 2 divisors, whose sum is σ = 1221001123292. Its totient is φ = 1221001123290.

The previous prime is 1221001123289. The next prime is 1221001123339. The reversal of 1221001123291 is 1923211001221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221001123291 - 2¹ = 1221001123289 is a prime.

Together with 1221001123289, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1221001123201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610500561645 + 610500561646.

It is an arithmetic number, because the mean of its divisors is an integer number (610500561646).

Almost surely, 2^{1221001123291} is an apocalyptic number.

1221001123291 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221001123291 is an equidigital number, since it uses as much as digits as its factorization.

1221001123291 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 25.

The spelling of 1221001123291 in words is "one trillion, two hundred twenty-one billion, one million, one hundred twenty-three thousand, two hundred ninety-one".