28121686272 has 216 divisors, whose sum is σ = 86048426464. Its totient is φ = 9155026944.

The previous prime is 28121686261. The next prime is 28121686289. The reversal of 28121686272 is 27268612182.

28121686272 is a `hidden beast` number, since 2 + 8 + 1 + 2 + 16 + 8 + 627 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (216).

It is an unprimeable number.

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, 2669688 + ... + 2680200.

Almost surely, 2^28121686272 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 28121686272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43024213232).

28121686272 is an abundant number, since it is smaller than the sum of its proper divisors (57926740192).

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

28121686272 is an equidigital number, since it uses as much as digits as its factorization.

28121686272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10587 (or 10561 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The spelling of 28121686272 in words is "twenty-eight billion, one hundred twenty-one million, six hundred eighty-six thousand, two hundred seventy-two".