128391660 has 36 divisors (see below), whose sum is σ = 389455248. Its totient is φ = 34237728.

The previous prime is 128391649. The next prime is 128391673. The reversal of 128391660 is 66193821.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 356464 + ... + 356823.

Almost surely, 2^128391660 is an apocalyptic number.

128391660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128391660 is an abundant number, since it is smaller than the sum of its proper divisors (261063588).

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

128391660 is a wasteful number, since it uses less digits than its factorization.

128391660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713302 (or 713297 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 128391660 is about 11331.0043685456. The cubic root of 128391660 is about 504.4819181122.

The spelling of 128391660 in words is "one hundred twenty-eight million, three hundred ninety-one thousand, six hundred sixty".