999903 has 8 divisors (see below), whose sum is σ = 1350400. Its totient is φ = 658008.

The previous prime is 999883. The next prime is 999907. The reversal of 999903 is 309999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 999903 - 2¹⁴ = 983519 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 (999907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1873 + ... + 2346.

It is an arithmetic number, because the mean of its divisors is an integer number (168800).

2⁹⁹⁹⁹⁰³ is an apocalyptic number.

999903 is a deficient number, since it is larger than the sum of its proper divisors (350497).

999903 is a wasteful number, since it uses less digits than its factorization.

999903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4301.

The product of its (nonzero) digits is 19683, while the sum is 39.

The square root of 999903 is about 999.9514988238. The cubic root of 999903 is about 99.9967665621.

The spelling of 999903 in words is "nine hundred ninety-nine thousand, nine hundred three".