999879 has 16 divisors (see below), whose sum is σ = 1427712. Its totient is φ = 620928.

The previous prime is 999863. The next prime is 999883. The reversal of 999879 is 978999.

It is not a de Polignac number, because 999879 - 2⁴ = 999863 is a prime.

999879 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999809) 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 15 ways as a sum of consecutive naturals, for example, 2799 + ... + 3135.

It is an arithmetic number, because the mean of its divisors is an integer number (89232).

2⁹⁹⁹⁸⁷⁹ is an apocalyptic number.

999879 is a deficient number, since it is larger than the sum of its proper divisors (427833).

999879 is a wasteful number, since it uses less digits than its factorization.

999879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406.

The product of its digits is 367416, while the sum is 51.

The square root of 999879 is about 999.9394981698. The cubic root of 999879 is about 99.9959665040.

The spelling of 999879 in words is "nine hundred ninety-nine thousand, eight hundred seventy-nine".