817889 has 2 divisors, whose sum is σ = 817890. Its totient is φ = 817888.

The previous prime is 817877. The next prime is 817891. The reversal of 817889 is 988718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 664225 + 153664 = 815^2 + 392^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-817889 is a prime.

Together with 817891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (814889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408944 + 408945.

It is an arithmetic number, because the mean of its divisors is an integer number (408945).

2⁸¹⁷⁸⁸⁹ is an apocalyptic number.

It is an amenable number.

817889 is a deficient number, since it is larger than the sum of its proper divisors (1).

817889 is an equidigital number, since it uses as much as digits as its factorization.

817889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 41.

The square root of 817889 is about 904.3721579085. The cubic root of 817889 is about 93.5186270761.

The spelling of 817889 in words is "eight hundred seventeen thousand, eight hundred eighty-nine".