28018565 has 4 divisors (see below), whose sum is σ = 33622284. Its totient is φ = 22414848.

The previous prime is 28018541. The next prime is 28018579. The reversal of 28018565 is 56581082.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22108804 + 5909761 = 4702^2 + 2431^2 .

It is a cyclic number.

It is not a de Polignac number, because 28018565 - 2¹⁰ = 28017541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2801852 + ... + 2801861.

It is an arithmetic number, because the mean of its divisors is an integer number (8405571).

Almost surely, 2^28018565 is an apocalyptic number.

It is an amenable number.

28018565 is a deficient number, since it is larger than the sum of its proper divisors (5603719).

28018565 is an equidigital number, since it uses as much as digits as its factorization.

28018565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5603718.

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 28018565 is about 5293.2565590570. The cubic root of 28018565 is about 303.7259945917.

The spelling of 28018565 in words is "twenty-eight million, eighteen thousand, five hundred sixty-five".