840859 has 2 divisors, whose sum is σ = 840860. Its totient is φ = 840858.

The previous prime is 840841. The next prime is 840863. The reversal of 840859 is 958048.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 840859 - 2⁹ = 840347 is a prime.

It is equal to p₆₆₉₄₉ and since 840859 and 66949 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (840839) 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, 420429 + 420430.

It is an arithmetic number, because the mean of its divisors is an integer number (420430).

2⁸⁴⁰⁸⁵⁹ is an apocalyptic number.

840859 is a deficient number, since it is larger than the sum of its proper divisors (1).

840859 is an equidigital number, since it uses as much as digits as its factorization.

840859 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 840859 is about 916.9836421660. The cubic root of 840859 is about 94.3860313407.

The spelling of 840859 in words is "eight hundred forty thousand, eight hundred fifty-nine".