28388839 has 4 divisors (see below), whose sum is σ = 29304640. Its totient is φ = 27473040.

The previous prime is 28388819. The next prime is 28388849. The reversal of 28388839 is 93888382.

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 28388839 - 2⁵ = 28388807 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28388792 and 28388801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28388809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 457854 + ... + 457915.

It is an arithmetic number, because the mean of its divisors is an integer number (7326160).

Almost surely, 2^28388839 is an apocalyptic number.

28388839 is a deficient number, since it is larger than the sum of its proper divisors (915801).

28388839 is an equidigital number, since it uses as much as digits as its factorization.

28388839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915800.

The product of its digits is 663552, while the sum is 49.

The square root of 28388839 is about 5328.1177727224. The cubic root of 28388839 is about 305.0580880136.

The spelling of 28388839 in words is "twenty-eight million, three hundred eighty-eight thousand, eight hundred thirty-nine".