128717728 has 24 divisors (see below), whose sum is σ = 256471488. Its totient is φ = 63582144.

The previous prime is 128717711. The next prime is 128717741. The reversal of 128717728 is 827717821.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21576 + ... + 26887.

It is an arithmetic number, because the mean of its divisors is an integer number (10686312).

Almost surely, 2^128717728 is an apocalyptic number.

It is an amenable number.

128717728 is a deficient number, since it is larger than the sum of its proper divisors (127753760).

128717728 is an equidigital number, since it uses as much as digits as its factorization.

128717728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48556 (or 48548 counting only the distinct ones).

The product of its digits is 87808, while the sum is 43.

The square root of 128717728 is about 11345.3835545565. The cubic root of 128717728 is about 504.9086237965.

The spelling of 128717728 in words is "one hundred twenty-eight million, seven hundred seventeen thousand, seven hundred twenty-eight".