28315217 has 16 divisors (see below), whose sum is σ = 34427520. Its totient is φ = 22733568.

The previous prime is 28315213. The next prime is 28315229. The reversal of 28315217 is 71251382.

It is a cyclic number.

It is not a de Polignac number, because 28315217 - 2² = 28315213 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28315217.

It is not an unprimeable number, because it can be changed into a prime (28315211) 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, 32534 + ... + 33392.

It is an arithmetic number, because the mean of its divisors is an integer number (2151720).

Almost surely, 2^28315217 is an apocalyptic number.

It is an amenable number.

28315217 is a deficient number, since it is larger than the sum of its proper divisors (6112303).

28315217 is a wasteful number, since it uses less digits than its factorization.

28315217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160.

The product of its digits is 3360, while the sum is 29.

The square root of 28315217 is about 5321.2044689149. The cubic root of 28315217 is about 304.7941529604.

Adding to 28315217 its reverse (71251382), we get a palindrome (99566599).

The spelling of 28315217 in words is "twenty-eight million, three hundred fifteen thousand, two hundred seventeen".