28506121938 has 128 divisors (see below), whose sum is σ = 78149836800. Its totient is φ = 7521788736.

The previous prime is 28506121927. The next prime is 28506121939. The reversal of 28506121938 is 83912160582.

28506121938 is a `hidden beast` number, since 28 + 5 + 0 + 612 + 1 + 9 + 3 + 8 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 28506121893 and 28506121902.

It is not an unprimeable number, because it can be changed into a prime (28506121939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 195595 + ... + 308657.

It is an arithmetic number, because the mean of its divisors is an integer number (610545600).

Almost surely, 2^28506121938 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28506121938, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39074918400).

28506121938 is an abundant number, since it is smaller than the sum of its proper divisors (49643714862).

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

28506121938 is a wasteful number, since it uses less digits than its factorization.

28506121938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113133 (or 113127 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 28506121938 in words is "twenty-eight billion, five hundred six million, one hundred twenty-one thousand, nine hundred thirty-eight".