28640000 has 90 divisors (see below), whose sum is σ = 71836380. Its totient is φ = 11392000.

The previous prime is 28639993. The next prime is 28640033. The reversal of 28640000 is 4682.

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

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 159911 + ... + 160089.

It is an arithmetic number, because the mean of its divisors is an integer number (798182).

Almost surely, 2^28640000 is an apocalyptic number.

28640000 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 28640000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35918190).

28640000 is an abundant number, since it is smaller than the sum of its proper divisors (43196380).

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

28640000 is an frugal number, since it uses more digits than its factorization.

28640000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 28640000 is about 5351.6352641039. The cubic root of 28640000 is about 305.9550819055.

Adding to 28640000 its reverse (4682), we get a palindrome (28644682).

The spelling of 28640000 in words is "twenty-eight million, six hundred forty thousand".