28308915 has 24 divisors (see below), whose sum is σ = 49214880. Its totient is φ = 15053184.

The previous prime is 28308913. The next prime is 28308919. The reversal of 28308915 is 51980382.

It is not a de Polignac number, because 28308915 - 2¹ = 28308913 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28308915.

It is not an unprimeable number, because it can be changed into a prime (28308911) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19039 + ... + 20471.

It is an arithmetic number, because the mean of its divisors is an integer number (2050620).

Almost surely, 2^28308915 is an apocalyptic number.

28308915 is a deficient number, since it is larger than the sum of its proper divisors (20905965).

28308915 is a wasteful number, since it uses less digits than its factorization.

28308915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1883 (or 1880 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 28308915 is about 5320.6122767967. The cubic root of 28308915 is about 304.7715390273.

The spelling of 28308915 in words is "twenty-eight million, three hundred eight thousand, nine hundred fifteen".