28440000 has 210 divisors, whose sum is σ = 103154480. Its totient is φ = 7488000.

The previous prime is 28439993. The next prime is 28440001. The reversal of 28440000 is 4482.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28440001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 359961 + ... + 360039.

Almost surely, 2^28440000 is an apocalyptic number.

28440000 is a gapful number since it is divisible by the number (20) 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 28440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51577240).

28440000 is an abundant number, since it is smaller than the sum of its proper divisors (74714480).

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

28440000 is an equidigital number, since it uses as much as digits as its factorization.

28440000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 28440000 is about 5332.9166503894. The cubic root of 28440000 is about 305.2412317105.

Adding to 28440000 its reverse (4482), we get a palindrome (28444482).

The spelling of 28440000 in words is "twenty-eight million, four hundred forty thousand".