28128399444 has 432 divisors, whose sum is σ = 86456885760. Its totient is φ = 7871800320.

The previous prime is 28128399433. The next prime is 28128399449. The reversal of 28128399444 is 44499382182.

It is a happy number.

28128399444 is a `hidden beast` number, since 28 + 12 + 83 + 99 + 444 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28128399449) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 760226994 + ... + 760227030.

It is an arithmetic number, because the mean of its divisors is an integer number (200131680).

Almost surely, 2^28128399444 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 28128399444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43228442880).

28128399444 is an abundant number, since it is smaller than the sum of its proper divisors (58328486316).

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

28128399444 is a wasteful number, since it uses less digits than its factorization.

28128399444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 109 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 54.

The spelling of 28128399444 in words is "twenty-eight billion, one hundred twenty-eight million, three hundred ninety-nine thousand, four hundred forty-four".