That's how many seconds there are in a single day, and the eight-hour workday has only 28,800 of them. As an entrepreneur, every second counts, and the old adage that there's not enough time in a day is a truism.

If some kind soul were to invent the time machine, we could all hit the "pause" button and get caught up. But since that day isn't coming any time soon, you might want to try some of these relatively simple hacks instead. They won't allow you to defy physics or alter the space-time continuum, but they will help you get the most out of every one of your 28,800 seconds.

Stop multitasking

One of the most frequently used phrases in job listings is "multitask." However, an overwhelming number of studies show that multitasking isn't really the act of doing two or more things at once.

In reality, multitasking involves rapidly shifting your attention between tasks, and it compromises the quality of all of them. So something as simple as talking on the phone while doing a report is likely to ruin both the report and the call.

Lawmakers seem to have caught on to this, and police officers now hand out huge tickets to drivers jabbering away on their iPhones. Maybe you should consider a "don't talk and type" law for your office? You and your team can avoid careless errors and ramp up productivity by prioritizing tasks instead of trying to tackle 10 of them at once.

Start prioritizing

In a perfect world, prioritizing would be easy as Sunday morning, just like the song goes. After your perfectly brewed morning cup of fair trade Ethiopian coffee, you'd simply order your tasks by importance--and boom! You're ready to start working.

You and I both know this is a fantasy. The unexpected project will always pop up in the middle of something important, without fail.

To be truly productive, you need a system to classify everything, so you know which "this" is more important than "that."

I recommend creating a Maslow-style business hierarchy to boost productivity. For me, clients are No. 1, and all queries need to be answered yesterday, so "clients and cash" sits at the top of my heap of priorities.

Of course, little things can pile up, and when they involve a deadline, they need to be turned around as quickly as possible, so this hierarchy can potentially make sealing an envelope more important than a very complex project. Knock out everything important first, and then you can commit your undivided attention to other tasks.

Technology is your friend

Is your technology working as hard as you are? If you're still using an Outlook events calendar or putting virtual sticky notes on your desktop, then it's time for an upgrade.

I strongly recommend considering a system that organizes and prioritizes your work in the virtual space. Most of these systems are designed in layman's terms, so you don't have to be Steve Jobs to figure them out.

I've implemented a system such as this and it has worked wonders. In real time, I can see every company task by priority, who's working on it, and how far along it is. I can even leave comments when I'm on the go.

Embrace this kind of technology and see a boost to your productivity almost immediately. It's worth the research.

What are your best productivity hacks? Please share in the comments.