128939520 has 160 divisors (see below), whose sum is σ = 418758912. Its totient is φ = 33841152.

The previous prime is 128939519. The next prime is 128939521. The reversal of 128939520 is 25939821.

It is an interprime number because it is at equal distance from previous prime (128939519) and next prime (128939521).

It is a tau number, because it is divible by the number of its divisors (160).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128939521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 790959 + ... + 791121.

Almost surely, 2^128939520 is an apocalyptic number.

128939520 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 128939520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (209379456).

128939520 is an abundant number, since it is smaller than the sum of its proper divisors (289819392).

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

128939520 is a wasteful number, since it uses less digits than its factorization.

128939520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 292 (or 276 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 128939520 is about 11355.1538959188. The cubic root of 128939520 is about 505.1984580897.

The spelling of 128939520 in words is "one hundred twenty-eight million, nine hundred thirty-nine thousand, five hundred twenty".