A report concluded that it would take 14 million Android phones to mine one bitcoin at the time of writing

On July 10, 2014, an intriguing analysis emerged from the security company Lookout, which provided a stark illustration of the impracticality of mining Bitcoin using mobile devices. The report wastitled “It Takes 14 Million Android Phones to Earn One Bitcoin”.
 

Lookout’s researchers had crunched the numbers and determined that mining Bitcoin on a mobile device was a highly inefficient endeavor. They calculated that if one were to mine continuously for 24 hours on a Samsung Galaxy SIII, the reward would be a minuscule 0.00000007 Bitcoin, equivalent to $0.00004473 at the time. To put this into perspective, to earn just one Bitcoin in a single day, one would need an astonishing 14,285,714 phones operating at full capacity simultaneously.
 

The report highlighted the vast gap between the computing power of consumer-grade mobile devices and the formidable requirements for Bitcoin mining. At that time, the value of one Bitcoin was over $600 USD, emphasizing the lucrative nature of the cryptocurrency and the substantial resources required to mine it.
 

Despite the overwhelming odds, Lookout’s principal security researcher, Marc Rogers, noted that there were numerous malicious Bitcoin miners targeting mobile devices. He observed a new mining variant detected every month, with malware creators becoming increasingly inventive in their attempts to make mobile mining profitable.