28305503 has 4 divisors (see below), whose sum is σ = 28350168. Its totient is φ = 28260840.

The previous prime is 28305469. The next prime is 28305517. The reversal of 28305503 is 30550382.

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 28305503 - 2¹⁸ = 28043359 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 (28305523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21368 + ... + 22653.

It is an arithmetic number, because the mean of its divisors is an integer number (7087542).

Almost surely, 2^28305503 is an apocalyptic number.

28305503 is a deficient number, since it is larger than the sum of its proper divisors (44665).

28305503 is an equidigital number, since it uses as much as digits as its factorization.

28305503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44664.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 28305503 is about 5320.2916273453. The cubic root of 28305503 is about 304.7592940946.

Adding to 28305503 its reverse (30550382), we get a palindrome (58855885).

The spelling of 28305503 in words is "twenty-eight million, three hundred five thousand, five hundred three".