809917 has 2 divisors, whose sum is σ = 809918. Its totient is φ = 809916.

The previous prime is 809909. The next prime is 809929. The reversal of 809917 is 719908.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 755161 + 54756 = 869^2 + 234^2 .

It is a cyclic number.

It is not a de Polignac number, because 809917 - 2³ = 809909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (806917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404958 + 404959.

It is an arithmetic number, because the mean of its divisors is an integer number (404959).

2⁸⁰⁹⁹¹⁷ is an apocalyptic number.

It is an amenable number.

809917 is a deficient number, since it is larger than the sum of its proper divisors (1).

809917 is an equidigital number, since it uses as much as digits as its factorization.

809917 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 34.

The square root of 809917 is about 899.9538877076. The cubic root of 809917 is about 93.2137911156.

Subtracting from 809917 its reverse (719908), we obtain a palindrome (90009).

The spelling of 809917 in words is "eight hundred nine thousand, nine hundred seventeen".