28280217 has 16 divisors (see below), whose sum is σ = 43908480. Its totient is φ = 15854592.

The previous prime is 28280209. The next prime is 28280237. The reversal of 28280217 is 71208282.

It is a happy number.

It is not a de Polignac number, because 28280217 - 2³ = 28280209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28280237) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11592 + ... + 13817.

It is an arithmetic number, because the mean of its divisors is an integer number (2744280).

Almost surely, 2^28280217 is an apocalyptic number.

It is an amenable number.

28280217 is a deficient number, since it is larger than the sum of its proper divisors (15628263).

28280217 is a wasteful number, since it uses less digits than its factorization.

28280217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25472.

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 28280217 is about 5317.9147228966. The cubic root of 28280217 is about 304.6685174078.

Adding to 28280217 its reverse (71208282), we get a palindrome (99488499).

The spelling of 28280217 in words is "twenty-eight million, two hundred eighty thousand, two hundred seventeen".