128505870 has 24 divisors (see below), whose sum is σ = 334115496. Its totient is φ = 34268208.

The previous prime is 128505859. The next prime is 128505901. The reversal of 128505870 is 78505821.

128505870 is a `hidden beast` number, since 1 + 28 + 50 + 587 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 713832 + ... + 714011.

It is an arithmetic number, because the mean of its divisors is an integer number (13921479).

Almost surely, 2^128505870 is an apocalyptic number.

128505870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

128505870 is an abundant number, since it is smaller than the sum of its proper divisors (205609626).

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

128505870 is a wasteful number, since it uses less digits than its factorization.

128505870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1427856 (or 1427853 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The square root of 128505870 is about 11336.0429603985. The cubic root of 128505870 is about 504.6314600270.

The spelling of 128505870 in words is "one hundred twenty-eight million, five hundred five thousand, eight hundred seventy".