is hatsune miku real?

No, and as much as her fans (like myself) would want her to be, she isn't.

She is a singing synthesizer (by Crypton Future Media, using Yamaha Vocaloid2 software) with a female gender. :)

It depends who are you asking.

for those that simply look on the brief, of course they will definitely say that miku is not real.
miku in fact is really a software generated voice, it doesnt exist a person called hatsune miku in this world.

but for me, miku is real.
she maybe just a software generated voice, but those producer, the lyric makers, the voice adjusters, they are REAL~!
and, not only them, we as the fans of miku too love her from the bottom of our heart, (if not, how she can even sings? Its because they produce the song with their HEART)

thats why she is real, because we MAKE HER REAL~~!

No. She's just a persona and a voice synth. The woman that provides the voice samples is called Saki Fujita.