128565 has 12 divisors (see below), whose sum is σ = 222924. Its totient is φ = 68544.

The previous prime is 128563. The next prime is 128591. The reversal of 128565 is 565821.

It can be written as a sum of positive squares in 2 ways, for example, as 66564 + 62001 = 258^2 + 249^2 .

It is not a de Polignac number, because 128565 - 2¹ = 128563 is a prime.

128565 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1384 + ... + 1473.

It is an arithmetic number, because the mean of its divisors is an integer number (18577).

2¹²⁸⁵⁶⁵ is an apocalyptic number.

128565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128565 is a deficient number, since it is larger than the sum of its proper divisors (94359).

128565 is a wasteful number, since it uses less digits than its factorization.

128565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2868 (or 2865 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 128565 is about 358.5596184737. The cubic root of 128565 is about 50.4708847627.

The spelling of 128565 in words is "one hundred twenty-eight thousand, five hundred sixty-five".