I must have slept through the English class where they told me this was OK.
Translation: "I can't be bothered to spell because you're teensy and I have another $1B to spend today on companies 100x bigger than yours. Make with the paperwork chop chop."
Then, confirmation: "Give me your mobile so I can call you any time I feel like to make you jump, because you're the bitch now."
But honestly, a lot of people seem to like doing business deals while walking around with their cell phones, so perhaps this is not actually a power play.
They had already met once. Given the context, it sounds like a continuation of the conversation, casual in nature, from a biz person to an engineer.
For something as important as an acquisition, I wouldn't want to feel like I'm dealing with an intern.