NEW YORK (AP) -- Avi Shenkar runs his four hair salons from the palm of his hand.
Work for the owner of Blo/Out Blow Dry Bars begins as soon as he grabs his iPhone at 6 a.m. while still in bed. He scrolls through messages on group texting app GroupMe to see if any of his stylists are running late or need the day off. He pumps pop and electronic dance music through the wireless speakers in his stores using an app for Sonos, a brand of wireless speakers. And he can see what's going on in each location by watching video on his phone from cameras with the Samsung iPolis app, a video camera security system.
"The phone is always with me," says Shenkar, whose salons do blowouts for $35. "It's an extension of me."
Smartphones have become vital for on-the-go entrepreneurs. Apps aimed at small business owners allow them to pay bills, update websites, market their companies, reach out to customers and keep in touch with employees from anywhere. Some owners say their smartphones makes it easier for them to build a side business while keeping a full-time job or step away from the company when needed.
They're also a big help for store owners, like Shenkar, who can't be at every location at once.
"Typically, I drive from one store to another," says Shenkar, who has three stores in Philadelphia and one in Atlantic City, which is only open in the spring and summer months.
Last year, he dropped his iPhone and shattered it before a drive to the Atlantic City shop.
"I had to immediately rush over to the Apple Store," he says. "I didn't care what the price was, I just got it."
Noah Chaimberg is also attached to his smartphone. He started Heatonist.com, a website that sells specialty hot sauces, in November. He still works a full-time marketing job in New York and relies on his iPhone to keep him connected to his business.
An app from online store creator Bigcommerce alerts him when an order is made on Heatonist.com. He pays suppliers using an app from payment processor PayPal. He also frequently uploads photos of hot sauce bottles to photo-sharing app Instagram, which helps him attract new customers.
When he goes to food festivals to sell carrot curry or red chili lime hot sauces, he turns his iPhone into a cash register with Square, a small device the size of a quarter that plugs into his phone and lets customers buy the sauces with their debit or credit cards.
"I'm constantly on the go," Chaimberg says.
Some entrepreneurs don't even have to be in the same state to run their business.
Kimberly Davison, who co-owns women's clothing store Goodbuy Girls in Nashville, Tennessee, moved to Los Angeles in April to earn some extra cash as a freelance marketing consultant to pay off a $10,000 dentist bill. She also wanted "to have fun" after running the store for nearly five years. Her co-owner, who drops by the shop a few days a week, was skeptical about the move, Davison says, but the arrangement is working.
Davison updates the stores website with an app from website and blog publishing platform WordPress on her Nokia Lumia smartphone. She gives out a Google Voice phone number to customers so that they can text her if they want to order a T-shirt or a vintage pair of cowboy boots. She uses Google's calendar to schedule employee work hours and special events, like if a country artist plans to stop by for a fitting. And she uses Instagram to post photos of new items she finds after meeting with clothing wholesalers in Los Angeles.
Often, customers ask to buy clothing straight from Instagram. That's when she'll respond with a link to the store's PayPal account to pay for the clothing.
"I literally do this sitting on the beach sometimes," says Davison. "It's crazy."