128406865 has 8 divisors (see below), whose sum is σ = 163152360. Its totient is φ = 96682752.

The previous prime is 128406853. The next prime is 128406869. The reversal of 128406865 is 568604821.

It can be written as a sum of positive squares in 4 ways, for example, as 4596736 + 123810129 = 2144^2 + 11127^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128406865 - 2⁹ = 128406353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128406869) 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, 755250 + ... + 755419.

It is an arithmetic number, because the mean of its divisors is an integer number (20394045).

Almost surely, 2^128406865 is an apocalyptic number.

It is an amenable number.

128406865 is a deficient number, since it is larger than the sum of its proper divisors (34745495).

128406865 is a wasteful number, since it uses less digits than its factorization.

128406865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1510691.

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 128406865 is about 11331.6752953833. The cubic root of 128406865 is about 504.5018320349.

The spelling of 128406865 in words is "one hundred twenty-eight million, four hundred six thousand, eight hundred sixty-five".