844643809 has 2 divisors, whose sum is σ = 844643810. Its totient is φ = 844643808.

The previous prime is 844643801. The next prime is 844643837. The reversal of 844643809 is 908346448.

It is a happy number.

844643809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 839376784 + 5267025 = 28972^2 + 2295^2 .

It is a cyclic number.

It is not a de Polignac number, because 844643809 - 2³ = 844643801 is a prime.

It is not a weakly prime, because it can be changed into another prime (844643801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 422321904 + 422321905.

It is an arithmetic number, because the mean of its divisors is an integer number (422321905).

Almost surely, 2^844643809 is an apocalyptic number.

It is an amenable number.

844643809 is a deficient number, since it is larger than the sum of its proper divisors (1).

844643809 is an equidigital number, since it uses as much as digits as its factorization.

844643809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 663552, while the sum is 46.

The square root of 844643809 is about 29062.7563902669. The cubic root of 844643809 is about 945.2743374539.

The spelling of 844643809 in words is "eight hundred forty-four million, six hundred forty-three thousand, eight hundred nine".