28712409 has 16 divisors (see below), whose sum is σ = 42474240. Its totient is φ = 17105360.

The previous prime is 28712389. The next prime is 28712413. The reversal of 28712409 is 90421782.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 28712409 - 2⁵ = 28712377 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a self number, because there is not a number n which added to its sum of digits gives 28712409.

It is not an unprimeable number, because it can be changed into a prime (28712419) 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, 5427 + ... + 9320.

It is an arithmetic number, because the mean of its divisors is an integer number (2654640).

Almost surely, 2^28712409 is an apocalyptic number.

It is an amenable number.

28712409 is a deficient number, since it is larger than the sum of its proper divisors (13761831).

28712409 is a wasteful number, since it uses less digits than its factorization.

28712409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14820.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 28712409 is about 5358.3961219753. The cubic root of 28712409 is about 306.2127082733.

The spelling of 28712409 in words is "twenty-eight million, seven hundred twelve thousand, four hundred nine".