Fun Facts About Prime Numbers, Pens, and Rivers

What Is a Prime Number?

A prime number is a whole number greater than 1 that can only be divided evenly by 1 and itself. That means it doesn’t break up into smaller parts without leaving a remainder.

The first prime number is 2 and it’s the only even one. All other even numbers can be divided by 2, so they’re not prime.

Here’s something amazing: there’s no end to prime numbers! Even very large numbers, like 102,359, can be prime.

How Was the Ballpoint Pen Invented?

A long time ago, people used pens that had to be dipped into ink over and over again. But in 1935, a journalist named László Bíró had a better idea. While visiting his newspaper’s printing press, he noticed the ink dried quickly and didn’t smudge.

He used that ink inside a little tube and added a small ball at the tip that rolled while writing, always staying wet with ink. It worked beautifully! The pen became especially popular with pilots and from there, it spread all over the world.

What Is the Longest River in the World?

The longest river in the world is the Amazon River in South America. It stretches over 7,000 kilometers and flows through nine different countries!

For a long time, people thought the Nile River in Africa was longer. But later, scientists discovered that the true beginning of the Amazon is in a stream connected to the Apurímac River in southern Peru, adding an extra 400 kilometers and giving the Amazon the title of the longest river on Earth.