28117517 has 4 divisors (see below), whose sum is σ = 28280220. Its totient is φ = 27954816.

The previous prime is 28117493. The next prime is 28117519. The reversal of 28117517 is 71571182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71571182 = 2 ⋅35785591.

It can be written as a sum of positive squares in 2 ways, for example, as 20967241 + 7150276 = 4579^2 + 2674^2 .

It is a cyclic number.

It is not a de Polignac number, because 28117517 - 2⁸ = 28117261 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 (28117519) 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 3 ways as a sum of consecutive naturals, for example, 81092 + ... + 81437.

It is an arithmetic number, because the mean of its divisors is an integer number (7070055).

Almost surely, 2^28117517 is an apocalyptic number.

It is an amenable number.

28117517 is a deficient number, since it is larger than the sum of its proper divisors (162703).

28117517 is a wasteful number, since it uses less digits than its factorization.

28117517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162702.

The product of its digits is 3920, while the sum is 32.

The square root of 28117517 is about 5302.5953079601. The cubic root of 28117517 is about 304.0831266500.

Adding to 28117517 its reverse (71571182), we get a palindrome (99688699).

The spelling of 28117517 in words is "twenty-eight million, one hundred seventeen thousand, five hundred seventeen".