128405685 has 16 divisors (see below), whose sum is σ = 205617600. Its totient is φ = 68426880.

The previous prime is 128405677. The next prime is 128405699. The reversal of 128405685 is 586504821.

It is not a de Polignac number, because 128405685 - 2³ = 128405677 is a prime.

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, 20841 + ... + 26289.

It is an arithmetic number, because the mean of its divisors is an integer number (12851100).

Almost surely, 2^128405685 is an apocalyptic number.

128405685 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128405685 is a deficient number, since it is larger than the sum of its proper divisors (77211915).

128405685 is a wasteful number, since it uses less digits than its factorization.

128405685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7028.

The product of its (nonzero) digits is 76800, while the sum is 39.

The square root of 128405685 is about 11331.6232288230. The cubic root of 128405685 is about 504.5002866502.

The spelling of 128405685 in words is "one hundred twenty-eight million, four hundred five thousand, six hundred eighty-five".