28539840 has 224 divisors, whose sum is σ = 107679744. Its totient is φ = 6266880.

The previous prime is 28539781. The next prime is 28539853. The reversal of 28539840 is 4893582.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (224).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 208252 + ... + 208388.

Almost surely, 2^28539840 is an apocalyptic number.

28539840 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 28539840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53839872).

28539840 is an abundant number, since it is smaller than the sum of its proper divisors (79139904).

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

28539840 is a wasteful number, since it uses less digits than its factorization.

28539840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 39.

The square root of 28539840 is about 5342.2691807883. The cubic root of 28539840 is about 305.5980026002.

The spelling of 28539840 in words is "twenty-eight million, five hundred thirty-nine thousand, eight hundred forty".