28509717 has 8 divisors (see below), whose sum is σ = 38039296. Its totient is φ = 18993312.

The previous prime is 28509667. The next prime is 28509727. The reversal of 28509717 is 71790582.

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

It is not a de Polignac number, because 28509717 - 2¹⁰ = 28508693 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 (28509727) 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 7 ways as a sum of consecutive naturals, for example, 4188 + ... + 8634.

It is an arithmetic number, because the mean of its divisors is an integer number (4754912).

Almost surely, 2^28509717 is an apocalyptic number.

It is an amenable number.

28509717 is a deficient number, since it is larger than the sum of its proper divisors (9529579).

28509717 is a wasteful number, since it uses less digits than its factorization.

28509717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6587.

The product of its (nonzero) digits is 35280, while the sum is 39.

The square root of 28509717 is about 5339.4491288896. The cubic root of 28509717 is about 305.4904480465.

The spelling of 28509717 in words is "twenty-eight million, five hundred nine thousand, seven hundred seventeen".