1320243121991 has 2 divisors, whose sum is σ = 1320243121992. Its totient is φ = 1320243121990.

The previous prime is 1320243121927. The next prime is 1320243121997. The reversal of 1320243121991 is 1991213420231.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1320243121991 - 2⁶ = 1320243121927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1320243121997) 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, 660121560995 + 660121560996.

It is an arithmetic number, because the mean of its divisors is an integer number (660121560996).

Almost surely, 2^{1320243121991} is an apocalyptic number.

1320243121991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1320243121991 is an equidigital number, since it uses as much as digits as its factorization.

1320243121991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 38.

The spelling of 1320243121991 in words is "one trillion, three hundred twenty billion, two hundred forty-three million, one hundred twenty-one thousand, nine hundred ninety-one".