28217 has 8 divisors (see below), whose sum is σ = 33600. Its totient is φ = 23184.

The previous prime is 28211. The next prime is 28219. The reversal of 28217 is 71282.

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

It is not a de Polignac number, because 28217 - 2⁴ = 28201 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 28217.

It is not an unprimeable number, because it can be changed into a prime (28211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 134 + ... + 272.

It is an arithmetic number, because the mean of its divisors is an integer number (4200).

28217 is a Friedman number, since it can be written as (21*8)^2-7, using all its digits and the basic arithmetic operations.

2²⁸²¹⁷ is an apocalyptic number.

It is an amenable number.

28217 is a deficient number, since it is larger than the sum of its proper divisors (5383).

28217 is a wasteful number, since it uses less digits than its factorization.

28217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175.

The product of its digits is 224, while the sum is 20.

The square root of 28217 is about 167.9791653748. The cubic root of 28217 is about 30.4441331518. Note that the first 3 decimals are identical.

Adding to 28217 its product of digits (224), we get a triangular number (28441 = T₂₃₈).

Adding to 28217 its reverse (71282), we get a palindrome (99499).

The spelling of 28217 in words is "twenty-eight thousand, two hundred seventeen".