28004000 has 48 divisors (see below), whose sum is σ = 68815656. Its totient is φ = 11200000.

The previous prime is 28003993. The next prime is 28004003. The reversal of 28004000 is 40082.

It can be written as a sum of positive squares in 4 ways, for example, as 7246864 + 20757136 = 2692^2 + 4556^2 .

It is not an unprimeable number, because it can be changed into a prime (28004003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 500 + ... + 7500.

Almost surely, 2^28004000 is an apocalyptic number.

28004000 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 28004000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34407828).

28004000 is an abundant number, since it is smaller than the sum of its proper divisors (40811656).

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

28004000 is an equidigital number, since it uses as much as digits as its factorization.

28004000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7026 (or 7008 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 28004000 is about 5291.8805731044. The cubic root of 28004000 is about 303.6733564465.

Adding to 28004000 its reverse (40082), we get a palindrome (28044082).

The spelling of 28004000 in words is "twenty-eight million, four thousand".