28003 has 4 divisors (see below), whose sum is σ = 28728. Its totient is φ = 27280.

The previous prime is 28001. The next prime is 28019. The reversal of 28003 is 30082.

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 28003 - 2¹ = 28001 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 8 and base 13.

It is not an unprimeable number, because it can be changed into a prime (28001) 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, 301 + ... + 382.

It is an arithmetic number, because the mean of its divisors is an integer number (7182).

2²⁸⁰⁰³ is an apocalyptic number.

28003 is a deficient number, since it is larger than the sum of its proper divisors (725).

28003 is an equidigital number, since it uses as much as digits as its factorization.

28003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 28003 is about 167.3409692813. The cubic root of 28003 is about 30.3669741761.

Adding to 28003 its reverse (30082), we get a palindrome (58085).

The spelling of 28003 in words is "twenty-eight thousand, three".