999806 has 4 divisors (see below), whose sum is σ = 1499712. Its totient is φ = 499902.

The previous prime is 999773. The next prime is 999809. The reversal of 999806 is 608999.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×999806² = 1999224075272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999809) by changing a digit.

999806 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 249950 + ... + 249953.

It is an arithmetic number, because the mean of its divisors is an integer number (374928).

2⁹⁹⁹⁸⁰⁶ is an apocalyptic number.

999806 is a deficient number, since it is larger than the sum of its proper divisors (499906).

999806 is a wasteful number, since it uses less digits than its factorization.

999806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499905.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 999806 is about 999.9029952950. The cubic root of 999806 is about 99.9935329151.

The spelling of 999806 in words is "nine hundred ninety-nine thousand, eight hundred six".