128138920 has 192 divisors, whose sum is σ = 372314880. Its totient is φ = 39320064.

The previous prime is 128138893. The next prime is 128138929. The reversal of 128138920 is 29831821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128138929) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1197507 + ... + 1197613.

It is an arithmetic number, because the mean of its divisors is an integer number (1939140).

Almost surely, 2^128138920 is an apocalyptic number.

128138920 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 128138920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (186157440).

128138920 is an abundant number, since it is smaller than the sum of its proper divisors (244175960).

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

128138920 is a wasteful number, since it uses less digits than its factorization.

128138920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 181 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 128138920 is about 11319.8462887090. The cubic root of 128138920 is about 504.1506751145.

The spelling of 128138920 in words is "one hundred twenty-eight million, one hundred thirty-eight thousand, nine hundred twenty".