28560921 has 4 divisors (see below), whose sum is σ = 38081232. Its totient is φ = 19040612.

The previous prime is 28560899. The next prime is 28560967. The reversal of 28560921 is 12906582.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28560921 - 2¹⁹ = 28036633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28560821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4760151 + ... + 4760156.

It is an arithmetic number, because the mean of its divisors is an integer number (9520308).

Almost surely, 2^28560921 is an apocalyptic number.

It is an amenable number.

28560921 is a deficient number, since it is larger than the sum of its proper divisors (9520311).

28560921 is an equidigital number, since it uses as much as digits as its factorization.

28560921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9520310.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 28560921 is about 5344.2418545571. The cubic root of 28560921 is about 305.6732275715.

The spelling of 28560921 in words is "twenty-eight million, five hundred sixty thousand, nine hundred twenty-one".