1285812509209 has 2 divisors, whose sum is σ = 1285812509210. Its totient is φ = 1285812509208.

The previous prime is 1285812509131. The next prime is 1285812509231. The reversal of 1285812509209 is 9029052185821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1040716224025 + 245096285184 = 1020155^2 + 495072^2 .

It is a cyclic number.

It is not a de Polignac number, because 1285812509209 - 2²¹ = 1285810412057 is a prime.

It is not a weakly prime, because it can be changed into another prime (1285812500209) 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, 642906254604 + 642906254605.

It is an arithmetic number, because the mean of its divisors is an integer number (642906254605).

Almost surely, 2^{1285812509209} is an apocalyptic number.

It is an amenable number.

1285812509209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1285812509209 is an equidigital number, since it uses as much as digits as its factorization.

1285812509209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1036800, while the sum is 52.

The spelling of 1285812509209 in words is "one trillion, two hundred eighty-five billion, eight hundred twelve million, five hundred nine thousand, two hundred nine".