28278720 has 140 divisors (see below), whose sum is σ = 100684584. Its totient is φ = 7534080.

The previous prime is 28278713. The next prime is 28278739. The reversal of 28278720 is 2787282.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25375 + ... + 26465.

Almost surely, 2^28278720 is an apocalyptic number.

28278720 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 28278720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50342292).

28278720 is an abundant number, since it is smaller than the sum of its proper divisors (72405864).

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

28278720 is a wasteful number, since it uses less digits than its factorization.

28278720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1120 (or 1101 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 36.

The square root of 28278720 is about 5317.7739703752. The cubic root of 28278720 is about 304.6631414846.

The spelling of 28278720 in words is "twenty-eight million, two hundred seventy-eight thousand, seven hundred twenty".