In his head, Dan Knights is thinking “Russia overhears a Bostonian rebel marmoset rashly reply heavily.”

But he’s saying: “468440901224953430146549585. ”

Knights, a University of Minnesota professor, is reciting the 652nd through 678th digits of pi, the mathematical constant of the ratio of a circle’s circumference to its diameter. He does it with the help of what he calls his “pi poem,” a mnemonic device that turns random numbers into a string of words.

We’re living in an age of digital amnesia, when many of us don’t know our kid’s phone number. Why bother to remember when we carry a world of information right in our pocket?

Yet there are still some people who commit to memory vast amounts of information: pages of poetry, dozens of bird songs, whole books of the Bible. For them, remembering information that can be accessed without Wi-Fi has benefits for the head and the heart.

“Anybody’s brain is like a Ferrari,” Knights said. “What would you do if you had a Ferrari? You’d take it out on the autobahn to see how fast it would go. These were my ways to take my brain for a test drive, revving it up, seeing how fast it would go.”

For others, having a poem, a passage or even a long string of numbers lodged in your mind can be a point of pride, a path to deeper understanding or a source of comfort.

On Pi Day — a day associated with eating pie and/or reciting parts of an infinite sequence of digits — we take a look at four of the memorizers in our midst.

The poetry of math

Even as a computer scientist studying the human microbiome, Knights really doesn’t need to know pi to the 2,000th digit.

No one does.

With only the first 40 digits of pi, you could calculate the circumference of the Milky Way galaxy to the exactness of the size of a proton.

The 38-year-old Knights started memorizing vast chunks of pi as a high school student, first by rote, and then using a technique that converts numbers into consonant sounds. Add vowels and the numbers become words and the words become a weird abstract poem. Then all you have to do is remember the poem.

In college, Knights’ pi poem stretched to 22 stanzas, representing more than 2,000 digits of pi crammed into his brain. (He considered trying for the North American record of pi memorization, but decided he didn’t have time to memorize more than 10,000 digits.)

Knights also has used his memory to accomplish other feats: He was the first kid in his elementary school to memorize the multiplication table. He made 1,500 tiny flash cards to study vocabulary words for the GRE graduate school entrance exam. And he believes he was the first person to solve a Rubik’s Cube blindfolded.

Except for getting the phone number “MEMORIZE PI,” Knights said, he didn’t really show off his memory feat.

“This was really for kind of secret bragging rights for myself,” he said. “I didn’t really do it for anybody. It’s all for me.”

Living works of art

Gary Westlund believes in exercising his mind while he’s exercising his body. The 66-year-old Anoka resident carries laminated sheets of poetry and memorizes verse while he’s running on the track or the treadmill.

Westlund, who runs a nonprofit that puts on 5K races, is known as “the poetry man” because he recites poems on the fly to fellow runners — even during a race. (He once got a request to recite the 23rd Psalm in the 23rd mile of a marathon.)

He knows the preamble to the Constitution, passages from Augustine’s “Confessions,” parts of “Moby Dick” and 40 or 50 poems. He said a 16-line sonnet might take him 40 minutes on a treadmill to learn.

But phone numbers? Westlund lets his phone remember those.

“They’re not significant enough. They’re not meaningful enough,” he said.

Westlund will “read” remembered poems in his head when he’s trying to fall asleep or needs comfort.

“I’ll never own any works of fine art,” he said. “But when it comes to great literary art, it costs me virtually nothing and I can hang it on the walls of my mind — and so can you.”

Learning by heart

St. Paul poet Naomi Cohn said what you care enough about to keep in your head is often an emotional decision: “This poem is important. I want to carry it around.”

Cohn, 53, started to lose her vision in her 30s due to retinal damage. Because she was unable to read print, she memorized practical things such as phone numbers and recipes.

But as a bird watcher, she also memorized the songs of about 100 bird species she no longer could identify by sight.

She even started a blog, Known by Heart, and led workshops devoted to memorizing and presenting poetry from memory.

Most poetry readings are just that: poets reading.

“There’s a little more adrenaline” when a poem is recited rather than read, she said. Maybe that’s because they’re demonstrating one definition of poetry: “It’s memorable language.”

Nearer, my God, to thee

Andy Naselli, 36, an assistant professor of theology and the New Testament at Bethlehem College and Seminary in Minneapolis, just spent more than a year memorizing the Book of Romans. Before that, it was First Corinthians.

Each of those books of the Bible takes him about an hour to recite aloud. His eventual aim is to have the entire New Testament memorized, for a total of about 20 hours of recitation. He wants to be word-perfect.

“I’m trying to show reverence for the text,” he said.

He said he typically spends about 45 minutes each morning memorizing verses. Like Westlund, he uses a treadmill.

“There’s something about walking and memory,” said Naselli, an elder at Bethlehem Baptist Church in Mounds View.

In his blog post about his “14 Reasons to Memorize an Entire Book of the Bible,” Naselli writes that memorizing scripture helps him to meditate on the text and really understand what it means. He can pray extended portions of the Bible while driving, walking or doing chores. Bible verses, he said, are always at hand to help resist sin.

Plus, having the text in his head lets him look people in the eye when reciting in sermons or when he’s counseling or teaching. “It’s right there, in the [random access memory] of my brain, to pour out at the right time,” he said. “The way I know God is through his word. So memorizing his word helps me know him.”

@RRChin