128909312 has 68 divisors (see below), whose sum is σ = 295696176. Its totient is φ = 55050240.

The previous prime is 128909311. The next prime is 128909323. The reversal of 128909312 is 213909821.

It is a super-2 number, since 2×128909312² = 33235221440626688, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128909311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 458612 + ... + 458892.

Almost surely, 2^128909312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128909312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147848088).

128909312 is an abundant number, since it is smaller than the sum of its proper divisors (166786864).

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

128909312 is an frugal number, since it uses more digits than its factorization.

128909312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 290 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 128909312 is about 11353.8236731068. The cubic root of 128909312 is about 505.1590023124.

The spelling of 128909312 in words is "one hundred twenty-eight million, nine hundred nine thousand, three hundred twelve".