28240000 has 80 divisors (see below), whose sum is σ = 70500870. Its totient is φ = 11264000.

The previous prime is 28239989. The next prime is 28240013. The reversal of 28240000 is 4282.

It can be written as a sum of positive squares in 5 ways, for example, as 107584 + 28132416 = 328^2 + 5304^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 79824 + ... + 80176.

Almost surely, 2^28240000 is an apocalyptic number.

28240000 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 28240000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35250435).

28240000 is an abundant number, since it is smaller than the sum of its proper divisors (42260870).

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

28240000 is an frugal number, since it uses more digits than its factorization.

28240000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 360 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 28240000 is about 5314.1321022346. The cubic root of 28240000 is about 304.5240269255.

Adding to 28240000 its reverse (4282), we get a palindrome (28244282).

The spelling of 28240000 in words is "twenty-eight million, two hundred forty thousand".