28644893 has 4 divisors (see below), whose sum is σ = 28656540. Its totient is φ = 28633248.

The previous prime is 28644887. The next prime is 28644901. The reversal of 28644893 is 39844682.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 39844682 = 2 ⋅19922341.

It can be written as a sum of positive squares in 2 ways, for example, as 14303524 + 14341369 = 3782^2 + 3787^2 .

It is a cyclic number.

It is not a de Polignac number, because 28644893 - 2⁶ = 28644829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28644883) by changing a digit.

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, 530 + ... + 7587.

It is an arithmetic number, because the mean of its divisors is an integer number (7164135).

Almost surely, 2^28644893 is an apocalyptic number.

It is an amenable number.

28644893 is a deficient number, since it is larger than the sum of its proper divisors (11647).

28644893 is an equidigital number, since it uses as much as digits as its factorization.

28644893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11646.

The product of its digits is 331776, while the sum is 44.

The square root of 28644893 is about 5352.0923945687. The cubic root of 28644893 is about 305.9725045425.

The spelling of 28644893 in words is "twenty-eight million, six hundred forty-four thousand, eight hundred ninety-three".