128391684 has 24 divisors (see below), whose sum is σ = 317203488. Its totient is φ = 40279680.

The previous prime is 128391673. The next prime is 128391689. The reversal of 128391684 is 486193821.

It is not an unprimeable number, because it can be changed into a prime (128391689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 314482 + ... + 314889.

It is an arithmetic number, because the mean of its divisors is an integer number (13216812).

Almost surely, 2^128391684 is an apocalyptic number.

It is an amenable number.

128391684 is an abundant number, since it is smaller than the sum of its proper divisors (188811804).

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

128391684 is a wasteful number, since it uses less digits than its factorization.

128391684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 629395 (or 629393 counting only the distinct ones).

The product of its digits is 82944, while the sum is 42.

The square root of 128391684 is about 11331.0054275867. The cubic root of 128391684 is about 504.4819495461.

The spelling of 128391684 in words is "one hundred twenty-eight million, three hundred ninety-one thousand, six hundred eighty-four".