28538809 has 8 divisors (see below), whose sum is σ = 30775752. Its totient is φ = 26307840.

The previous prime is 28538773. The next prime is 28538819. The reversal of 28538809 is 90883582.

It can be written as a sum of positive squares in 4 ways, for example, as 183184 + 28355625 = 428^2 + 5325^2 .

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

It is not a de Polignac number, because 28538809 - 2⁷ = 28538681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28538819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16887 + ... + 18499.

It is an arithmetic number, because the mean of its divisors is an integer number (3846969).

Almost surely, 2^28538809 is an apocalyptic number.

It is an amenable number.

28538809 is a deficient number, since it is larger than the sum of its proper divisors (2236943).

28538809 is a wasteful number, since it uses less digits than its factorization.

28538809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2987.

The product of its (nonzero) digits is 138240, while the sum is 43.

The square root of 28538809 is about 5342.1726853407. The cubic root of 28538809 is about 305.5943226527.

The spelling of 28538809 in words is "twenty-eight million, five hundred thirty-eight thousand, eight hundred nine".