128131891885728 has 144 divisors (see below), whose sum is σ = 368026940021832. Its totient is φ = 42282673920000.

The previous prime is 128131891885681. The next prime is 128131891885787. The reversal of 128131891885728 is 827588198131821.

It is a happy number.

128131891885728 is a `hidden beast` number, since 1 + 2 + 8 + 1 + 31 + 8 + 9 + 18 + 8 + 572 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 123984038275344 + 4147853610384 = 11134812^2 + 2036628^2 .

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

It is a Harshad number since it is a multiple of its sum of digits (72).

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, 245853258 + ... + 246373878.

Almost surely, 2^{128131891885728} is an apocalyptic number.

128131891885728 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 128131891885728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (184013470010916).

128131891885728 is an abundant number, since it is smaller than the sum of its proper divisors (239895048136104).

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

128131891885728 is a wasteful number, since it uses less digits than its factorization.

128131891885728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 529199 (or 529188 counting only the distinct ones).

The product of its digits is 123863040, while the sum is 72.

The spelling of 128131891885728 in words is "one hundred twenty-eight trillion, one hundred thirty-one billion, eight hundred ninety-one million, eight hundred eighty-five thousand, seven hundred twenty-eight".