128234391840 has 240 divisors, whose sum is σ = 479182572792. Its totient is φ = 32184262656.

The previous prime is 128234391839. The next prime is 128234391847. The reversal of 128234391840 is 48193432821.

128234391840 is a `hidden beast` number, since 1 + 28 + 234 + 391 + 8 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 128229880464 + 4511376 = 358092^2 + 2124^2 .

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (128234391847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 70699 + ... + 511338.

Almost surely, 2^128234391840 is an apocalyptic number.

128234391840 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 128234391840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239591286396).

128234391840 is an abundant number, since it is smaller than the sum of its proper divisors (350948180952).

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

128234391840 is a wasteful number, since it uses less digits than its factorization.

128234391840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582081 (or 582064 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The spelling of 128234391840 in words is "one hundred twenty-eight billion, two hundred thirty-four million, three hundred ninety-one thousand, eight hundred forty".