28187856 has 60 divisors (see below), whose sum is σ = 80205060. Its totient is φ = 9239040.

The previous prime is 28187807. The next prime is 28187893. The reversal of 28187856 is 65878182.

It can be written as a sum of positive squares in 2 ways, for example, as 6843456 + 21344400 = 2616^2 + 4620^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7180 + ... + 10388.

It is an arithmetic number, because the mean of its divisors is an integer number (1336751).

Almost surely, 2^28187856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28187856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40102530).

28187856 is an abundant number, since it is smaller than the sum of its proper divisors (52017204).

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

28187856 is a wasteful number, since it uses less digits than its factorization.

28187856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3284 (or 3275 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 28187856 is about 5309.2236720636. The cubic root of 28187856 is about 304.3364810773.

The spelling of 28187856 in words is "twenty-eight million, one hundred eighty-seven thousand, eight hundred fifty-six".