28079809 has 4 divisors (see below), whose sum is σ = 28265920. Its totient is φ = 27893700.

The previous prime is 28079791. The next prime is 28079833. The reversal of 28079809 is 90897082.

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-28079809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28079899) 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, 92829 + ... + 93130.

It is an arithmetic number, because the mean of its divisors is an integer number (7066480).

Almost surely, 2^28079809 is an apocalyptic number.

It is an amenable number.

28079809 is a deficient number, since it is larger than the sum of its proper divisors (186111).

28079809 is a wasteful number, since it uses less digits than its factorization.

28079809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186110.

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 28079809 is about 5299.0384976899. The cubic root of 28079809 is about 303.9471319940.

It can be divided in two parts, 280 and 79809, that added together give a square (80089 = 283²).

The spelling of 28079809 in words is "twenty-eight million, seventy-nine thousand, eight hundred nine".