1205611145209 has 2 divisors, whose sum is σ = 1205611145210. Its totient is φ = 1205611145208.

The previous prime is 1205611145153. The next prime is 1205611145231. The reversal of 1205611145209 is 9025411165021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 705846981609 + 499764163600 = 840147^2 + 706940^2 .

It is a cyclic number.

It is not a de Polignac number, because 1205611145209 - 2¹⁵ = 1205611112441 is a prime.

It is not a weakly prime, because it can be changed into another prime (1205611145239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 602805572604 + 602805572605.

It is an arithmetic number, because the mean of its divisors is an integer number (602805572605).

Almost surely, 2^{1205611145209} is an apocalyptic number.

It is an amenable number.

1205611145209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205611145209 is an equidigital number, since it uses as much as digits as its factorization.

1205611145209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 37.

The spelling of 1205611145209 in words is "one trillion, two hundred five billion, six hundred eleven million, one hundred forty-five thousand, two hundred nine".