28308513 has 8 divisors (see below), whose sum is σ = 37985728. Its totient is φ = 18751824.

The previous prime is 28308503. The next prime is 28308517. The reversal of 28308513 is 31580382.

It is a happy number.

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

It is not a de Polignac number, because 28308513 - 2⁸ = 28308257 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28308517) 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, 29581 + ... + 30522.

It is an arithmetic number, because the mean of its divisors is an integer number (4748216).

Almost surely, 2^28308513 is an apocalyptic number.

It is an amenable number.

28308513 is a deficient number, since it is larger than the sum of its proper divisors (9677215).

28308513 is a wasteful number, since it uses less digits than its factorization.

28308513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60263.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 28308513 is about 5320.5744990555. The cubic root of 28308513 is about 304.7700963870.

Adding to 28308513 its reverse (31580382), we get a palindrome (59888895).

The spelling of 28308513 in words is "twenty-eight million, three hundred eight thousand, five hundred thirteen".