Wiktionary
totient
n. (context mathematics English) The number of positive integers not more than a specified integer that are relatively prime to it.
Usage examples of "totient".
He and Randy look over at John Cantrell, who has crossed his arms over his chest and is unloading a disquisition on the Euler totient function while Harvard Li nods intently and his nerd-de-camp frantically scrawls notes on a legal pad.