128821320 has 128 divisors (see below), whose sum is σ = 432432000. Its totient is φ = 34110720.

The previous prime is 128821279. The next prime is 128821327. The reversal of 128821320 is 23128821.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (128821327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 195151 + ... + 195809.

It is an arithmetic number, because the mean of its divisors is an integer number (3378375).

Almost surely, 2^128821320 is an apocalyptic number.

128821320 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 128821320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (216216000).

128821320 is an abundant number, since it is smaller than the sum of its proper divisors (303610680).

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

128821320 is a wasteful number, since it uses less digits than its factorization.

128821320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 860 (or 850 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 128821320 is about 11349.9480175021. The cubic root of 128821320 is about 505.0440375935.

The spelling of 128821320 in words is "one hundred twenty-eight million, eight hundred twenty-one thousand, three hundred twenty".