28444509 has 12 divisors (see below), whose sum is σ = 41142556. Its totient is φ = 18937152.

The previous prime is 28444499. The next prime is 28444511. The reversal of 28444509 is 90544482.

It can be written as a sum of positive squares in 2 ways, for example, as 16040025 + 12404484 = 4005^2 + 3522^2 .

It is not a de Polignac number, because 28444509 - 2⁸ = 28444253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28444589) 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 11 ways as a sum of consecutive naturals, for example, 6747 + ... + 10119.

Almost surely, 2^28444509 is an apocalyptic number.

It is an amenable number.

28444509 is a deficient number, since it is larger than the sum of its proper divisors (12698047).

28444509 is a wasteful number, since it uses less digits than its factorization.

28444509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4316 (or 4313 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 28444509 is about 5333.3393854132. The cubic root of 28444509 is about 305.2573622776.

The spelling of 28444509 in words is "twenty-eight million, four hundred forty-four thousand, five hundred nine".