128396557728 has 144 divisors (see below), whose sum is σ = 382907528640. Its totient is φ = 42317738496.

The previous prime is 128396557673. The next prime is 128396557763. The reversal of 128396557728 is 827755693821.

128396557728 is a `hidden beast` number, since 1 + 2 + 8 + 3 + 9 + 6 + 557 + 72 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 599301 + ... + 784827.

It is an arithmetic number, because the mean of its divisors is an integer number (2659080060).

Almost surely, 2^128396557728 is an apocalyptic number.

128396557728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128396557728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191453764320).

128396557728 is an abundant number, since it is smaller than the sum of its proper divisors (254510970912).

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

128396557728 is an equidigital number, since it uses as much as digits as its factorization.

128396557728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185641 (or 185621 counting only the distinct ones).

The product of its digits is 50803200, while the sum is 63.

The spelling of 128396557728 in words is "one hundred twenty-eight billion, three hundred ninety-six million, five hundred fifty-seven thousand, seven hundred twenty-eight".