28280009 has 4 divisors (see below), whose sum is σ = 28620816. Its totient is φ = 27939204.

The previous prime is 28279997. The next prime is 28280047. The reversal of 28280009 is 90008282.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28280009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28280069) 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 3 ways as a sum of consecutive naturals, for example, 170279 + ... + 170444.

It is an arithmetic number, because the mean of its divisors is an integer number (7155204).

Almost surely, 2^28280009 is an apocalyptic number.

It is an amenable number.

28280009 is a deficient number, since it is larger than the sum of its proper divisors (340807).

28280009 is an equidigital number, since it uses as much as digits as its factorization.

28280009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340806.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 28280009 is about 5317.8951663229. The cubic root of 28280009 is about 304.6677704639.

The spelling of 28280009 in words is "twenty-eight million, two hundred eighty thousand, nine".