28380809 has 4 divisors (see below), whose sum is σ = 28984704. Its totient is φ = 27776916.

The previous prime is 28380797. The next prime is 28380857. The reversal of 28380809 is 90808382.

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 not a de Polignac number, because 28380809 - 2⁸ = 28380553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28388809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 301877 + ... + 301970.

It is an arithmetic number, because the mean of its divisors is an integer number (7246176).

Almost surely, 2^28380809 is an apocalyptic number.

It is an amenable number.

28380809 is a deficient number, since it is larger than the sum of its proper divisors (603895).

28380809 is an equidigital number, since it uses as much as digits as its factorization.

28380809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603894.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 28380809 is about 5327.3641700188. The cubic root of 28380809 is about 305.0293226310.

The spelling of 28380809 in words is "twenty-eight million, three hundred eighty thousand, eight hundred nine".