20840675209 has 2 divisors, whose sum is σ = 20840675210. Its totient is φ = 20840675208.

The previous prime is 20840675203. The next prime is 20840675221. The reversal of 20840675209 is 90257604802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18047235600 + 2793439609 = 134340^2 + 52853^2 .

It is a cyclic number.

It is not a de Polignac number, because 20840675209 - 2⁷ = 20840675081 is a prime.

It is not a weakly prime, because it can be changed into another prime (20840675203) 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, 10420337604 + 10420337605.

It is an arithmetic number, because the mean of its divisors is an integer number (10420337605).

Almost surely, 2^20840675209 is an apocalyptic number.

It is an amenable number.

20840675209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20840675209 is an equidigital number, since it uses as much as digits as its factorization.

20840675209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 43.

The spelling of 20840675209 in words is "twenty billion, eight hundred forty million, six hundred seventy-five thousand, two hundred nine".