28778443 has 4 divisors (see below), whose sum is σ = 29208040. Its totient is φ = 28348848.

The previous prime is 28778441. The next prime is 28778459. The reversal of 28778443 is 34487782.

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

It is a cyclic number.

It is not a de Polignac number, because 28778443 - 2¹ = 28778441 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28778443.

It is not an unprimeable number, because it can be changed into a prime (28778441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 214698 + ... + 214831.

It is an arithmetic number, because the mean of its divisors is an integer number (7302010).

Almost surely, 2^28778443 is an apocalyptic number.

28778443 is a deficient number, since it is larger than the sum of its proper divisors (429597).

28778443 is an equidigital number, since it uses as much as digits as its factorization.

28778443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429596.

The product of its digits is 301056, while the sum is 43.

The square root of 28778443 is about 5364.5543151319. The cubic root of 28778443 is about 306.4472754770.

The spelling of 28778443 in words is "twenty-eight million, seven hundred seventy-eight thousand, four hundred forty-three".