In “Born on a Blue Day: A Memoir” (Free Press, $24), Daniel Tammet reminds me of Data, the questing android of “Star Trek: The Next Generation.” As a multilingual savant who solves stumpers like 82 to the 4th power in his head and who learned Icelandic in a week, Tammet is a superhuman prodigy. As a young man with Asperger’s syndrome, he has learned normal human social behavior from the outside in, through observation and hard work.

Like Data, he also is a dogged – occasionally exasperating – explainer, as much to himself as to others.

The oldest child in a large, working-class English family, Tammet showed signs of high-functioning autism early, though his Asperger’s diagnosis wasn’t confirmed until he was 25. His parents are quiet heroes in his life story. Despite their own woes, they made the best life they could for this unusual, difficult child.

Tammet also has synesthesia, a neurological mixing of the senses. He sees numbers as color, shapes and motions. When he calculates in his head, he sees the numbers as shapes. He’s stunned scientists who’ve studied him by drawing this process in detail.

While watching the Seoul Olympics on TV, Tammet became fascinated with different countries. That led him to study alphabets and then languages. Astonishingly, for a sheltered lad, he volunteered after secondary school to go to Lithuania to teach English. He quickly grasped that language and added others: Romanian, Finnish, Esperanto. Today he runs an online language tutoring business, Optimnem, and devises his own invented language, Manti, in his free time.

Tammet’s calculating feats may remind American readers of the film “Rain Man”; Tammet describes his excitement when he meets Kim Peek, the real-life model for Dustin Hoffman’s movie character.

Tammet, who turned 28 on Wednesday, comes across as a warm and mellowing soul. In what’s bound to surprise some readers, he describes himself as both gay and a Christian. His worthy memoir broadens and deepens our understanding of who people with Asperger’s and savant syndrome are and can become.