128385 has 20 divisors (see below), whose sum is σ = 230868. Its totient is φ = 68256.

The previous prime is 128377. The next prime is 128389. The reversal of 128385 is 583821.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 23409 + 104976 = 153^2 + 324^2 .

It is not a de Polignac number, because 128385 - 2³ = 128377 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128389) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 247 + ... + 563.

2¹²⁸³⁸⁵ is an apocalyptic number.

128385 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128385 is a deficient number, since it is larger than the sum of its proper divisors (102483).

128385 is an equidigital number, since it uses as much as digits as its factorization.

128385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334 (or 325 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 128385 is about 358.3085262731. The cubic root of 128385 is about 50.4473195044.

Adding to 128385 its product of digits (1920), we get a triangular number (130305 = T₅₁₀).

The spelling of 128385 in words is "one hundred twenty-eight thousand, three hundred eighty-five".