28115709 has 16 divisors (see below), whose sum is σ = 38646720. Its totient is φ = 18170240.

The previous prime is 28115701. The next prime is 28115713. The reversal of 28115709 is 90751182.

It is a cyclic number.

It is not a de Polignac number, because 28115709 - 2³ = 28115701 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28115709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28115701) 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, 21379 + ... + 22655.

It is an arithmetic number, because the mean of its divisors is an integer number (2415420).

Almost surely, 2^28115709 is an apocalyptic number.

It is an amenable number.

28115709 is a deficient number, since it is larger than the sum of its proper divisors (10531011).

28115709 is a wasteful number, since it uses less digits than its factorization.

28115709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1500.

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 28115709 is about 5302.4248226637. The cubic root of 28115709 is about 304.0766088379.

The spelling of 28115709 in words is "twenty-eight million, one hundred fifteen thousand, seven hundred nine".