816839 has 2 divisors, whose sum is σ = 816840. Its totient is φ = 816838.

The previous prime is 816821. The next prime is 816841. The reversal of 816839 is 938618.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-816839 is a prime.

It is a Sophie Germain prime.

Together with 816841, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 816799 and 816808.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (816859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408419 + 408420.

It is an arithmetic number, because the mean of its divisors is an integer number (408420).

2⁸¹⁶⁸³⁹ is an apocalyptic number.

816839 is a deficient number, since it is larger than the sum of its proper divisors (1).

816839 is an equidigital number, since it uses as much as digits as its factorization.

816839 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 816839 is about 903.7914582469. The cubic root of 816839 is about 93.4785904253.

The spelling of 816839 in words is "eight hundred sixteen thousand, eight hundred thirty-nine".