128355840 has 200 divisors, whose sum is σ = 460472760. Its totient is φ = 34172928.

The previous prime is 128355791. The next prime is 128355863. The reversal of 128355840 is 48553821.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 128355795 and 128355804.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 207051 + ... + 207669.

Almost surely, 2^128355840 is an apocalyptic number.

128355840 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 128355840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (230236380).

128355840 is an abundant number, since it is smaller than the sum of its proper divisors (332116920).

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

128355840 is an frugal number, since it uses more digits than its factorization.

128355840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654 (or 629 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 36.

The square root of 128355840 is about 11329.4236393561. The cubic root of 128355840 is about 504.4349985976.

The spelling of 128355840 in words is "one hundred twenty-eight million, three hundred fifty-five thousand, eight hundred forty".