Intangibility: Unlike hardware, software is intangible. It cannot be seen or touched. It consists of instructions and data.

Non-Manufacturing: Software is developed or engineered; it is not manufactured in the traditional sense. This means there isn't a physical assembly process. The cost is largely in design and development rather than production.

Complexity: Software systems, especially large ones, are often incredibly complex. This complexity arises from the intricate interactions between different components, the need to manage vast amounts of data, and the requirement to meet diverse user needs.

Flexibility: Software is highly flexible and can be easily modified or adapted to meet new requirements or to fix bugs. This adaptability is a major advantage over hardware.

Maintainability: Software requires maintenance to correct errors, improve performance, and adapt to changing environments. Maintenance can be a significant portion of the software lifecycle cost.

Reliability: Users expect software to be reliable and to perform its intended functions correctly and consistently. Reliability is a critical factor in software quality.

Evolving Nature: Software is constantly evolving. New versions are released to add features, fix bugs, and improve performance. This continuous evolution is necessary to keep the software relevant and competitive.

Dependence on Hardware: Software depends on hardware to function. It requires a computer or other device to execute its instructions.

Error-Proneness: Software is prone to errors or bugs, which can cause it to malfunction or produce incorrect results. Thorough testing is essential to minimize the number of errors.

Reusability: Software components can often be reused in different applications, saving time and effort in development. This is a key principle of software engineering.