999859 has 4 divisors (see below), whose sum is σ = 1142704. Its totient is φ = 857016.

The previous prime is 999853. The next prime is 999863. The reversal of 999859 is 958999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 958999 = 599 ⋅1601.

It is a cyclic number.

It is not a de Polignac number, because 999859 - 2¹¹ = 997811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999853) 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 in 3 ways as a sum of consecutive naturals, for example, 71412 + ... + 71425.

It is an arithmetic number, because the mean of its divisors is an integer number (285676).

2⁹⁹⁹⁸⁵⁹ is an apocalyptic number.

999859 is a deficient number, since it is larger than the sum of its proper divisors (142845).

999859 is a wasteful number, since it uses less digits than its factorization.

999859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142844.

The product of its digits is 262440, while the sum is 49.

The square root of 999859 is about 999.9294975147. The cubic root of 999859 is about 99.9952997791.

The spelling of 999859 in words is "nine hundred ninety-nine thousand, eight hundred fifty-nine".