28017985 has 4 divisors (see below), whose sum is σ = 33621588. Its totient is φ = 22414384.

The previous prime is 28017967. The next prime is 28018009. The reversal of 28017985 is 58971082.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58971082 = 2 ⋅29485541.

It can be written as a sum of positive squares in 2 ways, for example, as 17048641 + 10969344 = 4129^2 + 3312^2 .

It is a cyclic number.

It is not a de Polignac number, because 28017985 - 2⁵ = 28017953 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2801794 + ... + 2801803.

It is an arithmetic number, because the mean of its divisors is an integer number (8405397).

Almost surely, 2^28017985 is an apocalyptic number.

It is an amenable number.

28017985 is a deficient number, since it is larger than the sum of its proper divisors (5603603).

28017985 is an equidigital number, since it uses as much as digits as its factorization.

28017985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5603602.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 28017985 is about 5293.2017720846. The cubic root of 28017985 is about 303.7238988111.

The spelling of 28017985 in words is "twenty-eight million, seventeen thousand, nine hundred eighty-five".