128739520 has 112 divisors (see below), whose sum is σ = 377391168. Its totient is φ = 40734720.

The previous prime is 128739517. The next prime is 128739551. The reversal of 128739520 is 25937821.

It is a tau number, because it is divible by the number of its divisors (112).

It is a self number, because there is not a number n which added to its sum of digits gives 128739520.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26910 + ... + 31330.

It is an arithmetic number, because the mean of its divisors is an integer number (3369564).

Almost surely, 2^128739520 is an apocalyptic number.

128739520 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 128739520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (188695584).

128739520 is an abundant number, since it is smaller than the sum of its proper divisors (248651648).

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

128739520 is a wasteful number, since it uses less digits than its factorization.

128739520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4458 (or 4448 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 128739520 is about 11346.3439045359. The cubic root of 128739520 is about 504.9371159812.

The spelling of 128739520 in words is "one hundred twenty-eight million, seven hundred thirty-nine thousand, five hundred twenty".