28317509 has 6 divisors (see below), whose sum is σ = 31125990. Its totient is φ = 25743080.

The previous prime is 28317491. The next prime is 28317533. The reversal of 28317509 is 90571382.

It can be written as a sum of positive squares in only one way, i.e., 19166884 + 9150625 = 4378^2 + 3025^2 .

It is not a de Polignac number, because 28317509 - 2¹² = 28313413 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 (28317409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 116894 + ... + 117135.

It is an arithmetic number, because the mean of its divisors is an integer number (5187665).

Almost surely, 2^28317509 is an apocalyptic number.

It is an amenable number.

28317509 is a deficient number, since it is larger than the sum of its proper divisors (2808481).

28317509 is a wasteful number, since it uses less digits than its factorization.

28317509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234051 (or 234040 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 28317509 is about 5321.4198293313. The cubic root of 28317509 is about 304.8023766816.

The spelling of 28317509 in words is "twenty-eight million, three hundred seventeen thousand, five hundred nine".