28440823 has 4 divisors (see below), whose sum is σ = 28907128. Its totient is φ = 27974520.

The previous prime is 28440821. The next prime is 28440833. The reversal of 28440823 is 32804482.

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 28440823 - 2¹ = 28440821 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 (28440821) 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, 233061 + ... + 233182.

It is an arithmetic number, because the mean of its divisors is an integer number (7226782).

Almost surely, 2^28440823 is an apocalyptic number.

28440823 is a deficient number, since it is larger than the sum of its proper divisors (466305).

28440823 is an equidigital number, since it uses as much as digits as its factorization.

28440823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466304.

The product of its (nonzero) digits is 12288, while the sum is 31.

The square root of 28440823 is about 5332.9938121097. The cubic root of 28440823 is about 305.2441760508.

The spelling of 28440823 in words is "twenty-eight million, four hundred forty thousand, eight hundred twenty-three".