28128384 has 80 divisors (see below), whose sum is σ = 83740470. Its totient is φ = 9372672.

The previous prime is 28128383. The next prime is 28128389. The reversal of 28128384 is 48382182.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 12446784 = 3960^2 + 3528^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (28128383) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 9012 + ... + 11724.

Almost surely, 2^28128384 is an apocalyptic number.

28128384 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28128384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41870235).

28128384 is an abundant number, since it is smaller than the sum of its proper divisors (55612086).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28128384 is an equidigital number, since it uses as much as digits as its factorization.

28128384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2739 (or 2718 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 28128384 is about 5303.6198958824. The cubic root of 28128384 is about 304.1222961319.

The spelling of 28128384 in words is "twenty-eight million, one hundred twenty-eight thousand, three hundred eighty-four".