28128987648 has 240 divisors, whose sum is σ = 83376750600. Its totient is φ = 9125855232.

The previous prime is 28128987643. The next prime is 28128987659. The reversal of 28128987648 is 84678982182.

28128987648 is a `hidden beast` number, since 281 + 289 + 8 + 76 + 4 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 14736017664 + 13392969984 = 121392^2 + 115728^2 .

It is a super-2 number, since 2×28128987648² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28128987643) 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 23 ways as a sum of consecutive naturals, for example, 36388990 + ... + 36389762.

Almost surely, 2^28128987648 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 28128987648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41688375300).

28128987648 is an abundant number, since it is smaller than the sum of its proper divisors (55247762952).

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

28128987648 is a wasteful number, since it uses less digits than its factorization.

28128987648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999 (or 980 counting only the distinct ones).

The product of its digits is 24772608, while the sum is 63.

The spelling of 28128987648 in words is "twenty-eight billion, one hundred twenty-eight million, nine hundred eighty-seven thousand, six hundred forty-eight".