NBCUniversal and Comcast Ventures are taking a bet on millennial-focused financial technology app, Acorns.

The companies announced an equity investment in the start-up on Monday that includes a strategic partnership with Comcast-owned CNBC to produce original content with Acorns. The two will team up on articles, videos and eventually live conferences with the aim of increasing financial literacy, the companies said.

The investment was part of Acorns' latest $105 million funding round, which puts its valuation at $860 million. BlackRock, Bain Capital Ventures, TPG's Rise Fund, DST and Michael Dell's MSD Capital also took part in the Series E round. NBCUniversal, which is now Acorns' biggest shareholder, will also receive a seat on the start-up's board. It will be filled by CNBC Chairman Mark Hoffman.

"This partnership with Acorns builds on CNBC's 30-year commitment to democratizing the financial markets helping generations invest for their future," Hoffman said in a statement. "We are excited to bring together two brands with this shared social purpose to drive value to our viewers, users and customers."

The Irvine, California-based start-up tries to facilitate smart investing by consumers through various services and education offerings. One of its most popular offerings allows customers to automatically invest the spare change from debit or credit card purchases. For example, if an Acorns user bought a cup of coffee for $2.75, the mobile app would round up to the nearest dollar and put that remaining 25 cents into an Acorns investment account. That money is then put to work in professionally managed index funds.

Its automated retirement account service "Acorns Later" has ushered in 350,000 investors who have invested $40 million to date, according to the company.

The 6-year-old start-up already produces its own educational content through its site "Grow." CNBC is bringing on a team of about 20 people to expand that effort, which Acorns CEO Noah Kerner said will "take things to the next level" and get useful investing content in front of its 4.5 million customers.

"We're trying to put the tools of wealth-making in everyone's hands," Kerner told CNBC. "We have an imperative to educate people and make them smarter with their money so that they can make the right financial decisions."

Kerner told CNBC the cash injection should help the start-up expand its product offering and team. Its last publicly disclosed deal was a $50 million investment from BlackRock and inside capital in May, according to Pitchbook. In addition to Monday's investment from NBCUniversal and Comcast Ventures, the venture capital arm of NBCUniversal's parent company, Acorns has also attracted minority investments from PayPal Holdings and Greycroft, among others, according to Pitchbook.