853866809 has 2 divisors, whose sum is σ = 853866810. Its totient is φ = 853866808.

The previous prime is 853866791. The next prime is 853866851. The reversal of 853866809 is 908668358.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 672883600 + 180983209 = 25940^2 + 13453^2 .

It is a cyclic number.

It is not a de Polignac number, because 853866809 - 2⁸ = 853866553 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (853866509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 426933404 + 426933405.

It is an arithmetic number, because the mean of its divisors is an integer number (426933405).

Almost surely, 2^853866809 is an apocalyptic number.

It is an amenable number.

853866809 is a deficient number, since it is larger than the sum of its proper divisors (1).

853866809 is an equidigital number, since it uses as much as digits as its factorization.

853866809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2488320, while the sum is 53.

The square root of 853866809 is about 29220.9994524486. Note that the first 3 decimals coincide. The cubic root of 853866809 is about 948.7024979414.

The spelling of 853866809 in words is "eight hundred fifty-three million, eight hundred sixty-six thousand, eight hundred nine".