999503 has 4 divisors (see below), whose sum is σ = 1004928. Its totient is φ = 994080.

The previous prime is 999499. The next prime is 999521. The reversal of 999503 is 305999.

999503 is nontrivially palindromic in base 16.

999503 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 999503 - 2² = 999499 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 (999553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2426 + ... + 2807.

It is an arithmetic number, because the mean of its divisors is an integer number (251232).

2⁹⁹⁹⁵⁰³ is an apocalyptic number.

999503 is a deficient number, since it is larger than the sum of its proper divisors (5425).

999503 is a wasteful number, since it uses less digits than its factorization.

999503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5424.

The product of its (nonzero) digits is 10935, while the sum is 35.

The square root of 999503 is about 999.7514691162. The cubic root of 999503 is about 99.9834305880.

The spelling of 999503 in words is "nine hundred ninety-nine thousand, five hundred three".