28881209 has 8 divisors (see below), whose sum is σ = 33459840. Its totient is φ = 24415776.

The previous prime is 28881163. The next prime is 28881227. The reversal of 28881209 is 90218882.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28881209 - 2¹² = 28877113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28881239) 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 7 ways as a sum of consecutive naturals, for example, 27749 + ... + 28770.

It is an arithmetic number, because the mean of its divisors is an integer number (4182480).

Almost surely, 2^28881209 is an apocalyptic number.

It is an amenable number.

28881209 is a deficient number, since it is larger than the sum of its proper divisors (4578631).

28881209 is an equidigital number, since it uses as much as digits as its factorization.

28881209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56599.

The product of its (nonzero) digits is 18432, while the sum is 38.

The square root of 28881209 is about 5374.1240216430. The cubic root of 28881209 is about 306.8116100956.

The spelling of 28881209 in words is "twenty-eight million, eight hundred eighty-one thousand, two hundred nine".