28280000 has 140 divisors (see below), whose sum is σ = 80936592. Its totient is φ = 9600000.

The previous prime is 28279997. The next prime is 28280047. The reversal of 28280000 is 8282.

It is a tau number, because it is divible by the number of its divisors (140).

It is a Harshad number since it is a multiple of its sum of digits (20).

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 19 ways as a sum of consecutive naturals, for example, 279950 + ... + 280050.

Almost surely, 2^28280000 is an apocalyptic number.

28280000 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 28280000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40468296).

28280000 is an abundant number, since it is smaller than the sum of its proper divisors (52656592).

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

28280000 is an equidigital number, since it uses as much as digits as its factorization.

28280000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 28280000 is about 5317.8943201233. The cubic root of 28280000 is about 304.6677381441.

Adding to 28280000 its reverse (8282), we get a palindrome (28288282).

It can be divided in two parts, 28 and 280000, that multiplied together give a square (7840000 = 2800²).

The spelling of 28280000 in words is "twenty-eight million, two hundred eighty thousand".