28128388775 has 48 divisors (see below), whose sum is σ = 36802073088. Its totient is φ = 21285264000.

The previous prime is 28128388723. The next prime is 28128388777. The reversal of 28128388775 is 57788382182.

It is a happy number.

It is not a de Polignac number, because 28128388775 - 2¹⁶ = 28128323239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28128388777) 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 47 ways as a sum of consecutive naturals, for example, 31711382 + ... + 31712268.

It is an arithmetic number, because the mean of its divisors is an integer number (766709856).

Almost surely, 2^28128388775 is an apocalyptic number.

28128388775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28128388775 is a deficient number, since it is larger than the sum of its proper divisors (8673684313).

28128388775 is a wasteful number, since it uses less digits than its factorization.

28128388775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1472 (or 1467 counting only the distinct ones).

The product of its digits is 12042240, while the sum is 59.

The spelling of 28128388775 in words is "twenty-eight billion, one hundred twenty-eight million, three hundred eighty-eight thousand, seven hundred seventy-five".