28438720 has 56 divisors (see below), whose sum is σ = 68232528. Its totient is φ = 11289600.

The previous prime is 28438703. The next prime is 28438733. The reversal of 28438720 is 2783482.

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 7 ways as a sum of consecutive naturals, for example, 57675 + ... + 58165.

It is an arithmetic number, because the mean of its divisors is an integer number (1218438).

Almost surely, 2^28438720 is an apocalyptic number.

28438720 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 28438720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34116264).

28438720 is an abundant number, since it is smaller than the sum of its proper divisors (39793808).

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

28438720 is a wasteful number, since it uses less digits than its factorization.

28438720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689 (or 679 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 28438720 is about 5332.7966396629. The cubic root of 28438720 is about 305.2366523078.

The spelling of 28438720 in words is "twenty-eight million, four hundred thirty-eight thousand, seven hundred twenty".