This is a number used by QFact Marketing to alert you to surveys and studies they are conducting that you may be eligible to participate in. Not spam, unless you consider someone calling to whom you have, in effect, given your number and said "call me" a spammer. Unusual that they did not leave a message, as they always leave a prerecorded message on my cell with basic information on the survey/study and how to start the prescreening process.