28304400 has 120 divisors (see below), whose sum is σ = 91948480. Its totient is φ = 7441920.

The previous prime is 28304399. The next prime is 28304407. The reversal of 28304400 is 440382.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×28304400² = 1602278118720000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28304407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 123486 + ... + 123714.

Almost surely, 2^28304400 is an apocalyptic number.

28304400 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 28304400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45974240).

28304400 is an abundant number, since it is smaller than the sum of its proper divisors (63644080).

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

28304400 is a wasteful number, since it uses less digits than its factorization.

28304400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353 (or 342 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 28304400 is about 5320.1879666042. The cubic root of 28304400 is about 304.7553354549.

Adding to 28304400 its reverse (440382), we get a palindrome (28744782).

The spelling of 28304400 in words is "twenty-eight million, three hundred four thousand, four hundred".