999823 has 6 divisors (see below), whose sum is σ = 1099112. Its totient is φ = 908820.

The previous prime is 999809. The next prime is 999853. The reversal of 999823 is 328999.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-999823 is a prime.

It is a Duffinian number.

It is a congruent 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 5 ways as a sum of consecutive naturals, for example, 4011 + ... + 4252.

2⁹⁹⁹⁸²³ is an apocalyptic number.

999823 is a deficient number, since it is larger than the sum of its proper divisors (99289).

999823 is a wasteful number, since it uses less digits than its factorization.

999823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8285 (or 8274 counting only the distinct ones).

The product of its digits is 34992, while the sum is 40.

The square root of 999823 is about 999.9114960835. The cubic root of 999823 is about 99.9940996519.

The spelling of 999823 in words is "nine hundred ninety-nine thousand, eight hundred twenty-three".