128765 has 16 divisors (see below), whose sum is σ = 190848. Its totient is φ = 81216.

The previous prime is 128761. The next prime is 128767. The reversal of 128765 is 567821.

It is a cyclic number.

It is not a de Polignac number, because 128765 - 2² = 128761 is a prime.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 128765.

It is not an unprimeable number, because it can be changed into a prime (128761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 314 + ... + 596.

It is an arithmetic number, because the mean of its divisors is an integer number (11928).

2¹²⁸⁷⁶⁵ is an apocalyptic number.

It is an amenable number.

128765 is a deficient number, since it is larger than the sum of its proper divisors (62083).

128765 is a wasteful number, since it uses less digits than its factorization.

128765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308.

The product of its digits is 3360, while the sum is 29.

The square root of 128765 is about 358.8384037419. The cubic root of 128765 is about 50.4970426004.

The spelling of 128765 in words is "one hundred twenty-eight thousand, seven hundred sixty-five".