1209323519891 has 2 divisors, whose sum is σ = 1209323519892. Its totient is φ = 1209323519890.

The previous prime is 1209323519861. The next prime is 1209323520019. The reversal of 1209323519891 is 1989153239021.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1209323519891 - 2⁶ = 1209323519827 is a prime.

It is not a weakly prime, because it can be changed into another prime (1209323519861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 604661759945 + 604661759946.

It is an arithmetic number, because the mean of its divisors is an integer number (604661759946).

Almost surely, 2^{1209323519891} is an apocalyptic number.

1209323519891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1209323519891 is an equidigital number, since it uses as much as digits as its factorization.

1209323519891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1049760, while the sum is 53.

The spelling of 1209323519891 in words is "one trillion, two hundred nine billion, three hundred twenty-three million, five hundred nineteen thousand, eight hundred ninety-one".