128709720 has 96 divisors (see below), whose sum is σ = 442933920. Its totient is φ = 32302080.

The previous prime is 128709697. The next prime is 128709761. The reversal of 128709720 is 27907821.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4396 + ... + 16635.

It is an arithmetic number, because the mean of its divisors is an integer number (4613895).

Almost surely, 2^128709720 is an apocalyptic number.

128709720 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 128709720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221466960).

128709720 is an abundant number, since it is smaller than the sum of its proper divisors (314224200).

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

128709720 is a wasteful number, since it uses less digits than its factorization.

128709720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21065 (or 21058 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 128709720 is about 11345.0306301922. The cubic root of 128709720 is about 504.8981528428.

The spelling of 128709720 in words is "one hundred twenty-eight million, seven hundred nine thousand, seven hundred twenty".