1205643320309 has 2 divisors, whose sum is σ = 1205643320310. Its totient is φ = 1205643320308.

The previous prime is 1205643320303. The next prime is 1205643320351. The reversal of 1205643320309 is 9030233465021.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1152878933284 + 52764387025 = 1073722^2 + 229705^2 .

It is a cyclic number.

It is not a de Polignac number, because 1205643320309 - 2²⁸ = 1205374884853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1205643320303) 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, 602821660154 + 602821660155.

It is an arithmetic number, because the mean of its divisors is an integer number (602821660155).

Almost surely, 2^{1205643320309} is an apocalyptic number.

It is an amenable number.

1205643320309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205643320309 is an equidigital number, since it uses as much as digits as its factorization.

1205643320309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 38.

The spelling of 1205643320309 in words is "one trillion, two hundred five billion, six hundred forty-three million, three hundred twenty thousand, three hundred nine".