28784239 has 4 divisors (see below), whose sum is σ = 31401000. Its totient is φ = 26167480.

The previous prime is 28784233. The next prime is 28784251. The reversal of 28784239 is 93248782.

It is a happy number.

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 28784239 - 2⁵ = 28784207 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28784195 and 28784204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28784233) 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, 1308364 + ... + 1308385.

It is an arithmetic number, because the mean of its divisors is an integer number (7850250).

Almost surely, 2^28784239 is an apocalyptic number.

28784239 is a deficient number, since it is larger than the sum of its proper divisors (2616761).

28784239 is a wasteful number, since it uses less digits than its factorization.

28784239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2616760.

The product of its digits is 193536, while the sum is 43.

The square root of 28784239 is about 5365.0945005657. The cubic root of 28784239 is about 306.4678469998.

It can be divided in two parts, 2878 and 4239, that added together give a palindrome (7117).

The spelling of 28784239 in words is "twenty-eight million, seven hundred eighty-four thousand, two hundred thirty-nine".