28987856 has 30 divisors (see below), whose sum is σ = 59671590. Its totient is φ = 13639168.

The previous prime is 28987853. The next prime is 28987859. The reversal of 28987856 is 65878982.

It is an interprime number because it is at equal distance from previous prime (28987853) and next prime (28987859).

It can be written as a sum of positive squares in 3 ways, for example, as 9096256 + 19891600 = 3016^2 + 4460^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28987798 and 28987807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28987853) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1490 + ... + 7758.

It is an arithmetic number, because the mean of its divisors is an integer number (1989053).

Almost surely, 2^28987856 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 28987856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29835795).

28987856 is an abundant number, since it is smaller than the sum of its proper divisors (30683734).

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

28987856 is a wasteful number, since it uses less digits than its factorization.

28987856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6311 (or 6288 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 53.

The square root of 28987856 is about 5384.0371469744. The cubic root of 28987856 is about 307.1887912758.

The spelling of 28987856 in words is "twenty-eight million, nine hundred eighty-seven thousand, eight hundred fifty-six".