28456809 has 4 divisors (see below), whose sum is σ = 37942416. Its totient is φ = 18971204.

The previous prime is 28456789. The next prime is 28456817. The reversal of 28456809 is 90865482.

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 28456809 - 2⁵ = 28456777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28456609) 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, 4742799 + ... + 4742804.

It is an arithmetic number, because the mean of its divisors is an integer number (9485604).

Almost surely, 2^28456809 is an apocalyptic number.

It is an amenable number.

28456809 is a deficient number, since it is larger than the sum of its proper divisors (9485607).

28456809 is an equidigital number, since it uses as much as digits as its factorization.

28456809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9485606.

The product of its (nonzero) digits is 138240, while the sum is 42.

The square root of 28456809 is about 5334.4923844730. The cubic root of 28456809 is about 305.3013558241.

The spelling of 28456809 in words is "twenty-eight million, four hundred fifty-six thousand, eight hundred nine".