128995840 has 80 divisors (see below), whose sum is σ = 317089080. Its totient is φ = 50298880.

The previous prime is 128995787. The next prime is 128995843. The reversal of 128995840 is 48599821.

It can be written as a sum of positive squares in 4 ways, for example, as 108493056 + 20502784 = 10416^2 + 4528^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128995843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104346 + ... + 105574.

Almost surely, 2^128995840 is an apocalyptic number.

128995840 is a gapful number since it is divisible by the number (10) 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 128995840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158544540).

128995840 is an abundant number, since it is smaller than the sum of its proper divisors (188093240).

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

128995840 is an equidigital number, since it uses as much as digits as its factorization.

128995840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1293 (or 1277 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 46.

The square root of 128995840 is about 11357.6335563356. The cubic root of 128995840 is about 505.2720032565.

The spelling of 128995840 in words is "one hundred twenty-eight million, nine hundred ninety-five thousand, eight hundred forty".