809665873 has 2 divisors, whose sum is σ = 809665874. Its totient is φ = 809665872.

The previous prime is 809665853. The next prime is 809665889. The reversal of 809665873 is 378566908.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 475763344 + 333902529 = 21812^2 + 18273^2 .

It is a cyclic number.

It is not a de Polignac number, because 809665873 - 2²¹ = 807568721 is a prime.

It is a nialpdrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 809665873.

It is not a weakly prime, because it can be changed into another prime (809665853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404832936 + 404832937.

It is an arithmetic number, because the mean of its divisors is an integer number (404832937).

Almost surely, 2^809665873 is an apocalyptic number.

It is an amenable number.

809665873 is a deficient number, since it is larger than the sum of its proper divisors (1).

809665873 is an equidigital number, since it uses as much as digits as its factorization.

809665873 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2177280, while the sum is 52.

The square root of 809665873 is about 28454.6283229987. The cubic root of 809665873 is about 932.0415600500.

The spelling of 809665873 in words is "eight hundred nine million, six hundred sixty-five thousand, eight hundred seventy-three".