28644840 has 192 divisors, whose sum is σ = 110597760. Its totient is φ = 6531840.

The previous prime is 28644829. The next prime is 28644883. The reversal of 28644840 is 4844682.

28644840 is a `hidden beast` number, since 2 + 8 + 644 + 8 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28644795 and 28644804.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 67830 + ... + 68250.

It is an arithmetic number, because the mean of its divisors is an integer number (576030).

Almost surely, 2^28644840 is an apocalyptic number.

28644840 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 28644840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55298880).

28644840 is an abundant number, since it is smaller than the sum of its proper divisors (81952920).

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

28644840 is a wasteful number, since it uses less digits than its factorization.

28644840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 36.

The square root of 28644840 is about 5352.0874432318. The cubic root of 28644840 is about 305.9723158346.

The spelling of 28644840 in words is "twenty-eight million, six hundred forty-four thousand, eight hundred forty".