28538440 has 64 divisors (see below), whose sum is σ = 73872000. Its totient is φ = 9719808.

The previous prime is 28538431. The next prime is 28538443. The reversal of 28538440 is 4483582.

It is a junction number, because it is equal to n+sod(n) for n = 28538396 and 28538405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28538443) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 63336 + ... + 63784.

It is an arithmetic number, because the mean of its divisors is an integer number (1154250).

Almost surely, 2^28538440 is an apocalyptic number.

28538440 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 28538440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36936000).

28538440 is an abundant number, since it is smaller than the sum of its proper divisors (45333560).

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

28538440 is a wasteful number, since it uses less digits than its factorization.

28538440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694 (or 690 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 34.

The square root of 28538440 is about 5342.1381487191. The cubic root of 28538440 is about 305.5930055598.

The spelling of 28538440 in words is "twenty-eight million, five hundred thirty-eight thousand, four hundred forty".