Number Trivia

Can you find out which number multiplied by itself will give the output as 12345678987654321?




Similar Riddles

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.

How can the swan successfully escape?

Asked by Neha on 22 Apr 2022


The picture shows the dice results in each couple of throws. If they are actually following a pattern, can you find out the missing one?

Next Dice Movement

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A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

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Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Arrange The Marbles Puzzle

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If in a code language, DISTANCE is written as IDTUBECN and DOCUMENT is written as ODDVNTNE, the how will THURSDAY be coded as in the same language?

Asked by Neha on 17 May 2021

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?

Two Door Two Guard

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If a wheel has 54 spokes, how many spaces are there between the spokes?

Asked by Neha on 27 Sep 2021

A wealthy man lives alone in a small cottage. Being partially handicapped he had everything delivered to his cottage. The mailman was delivering a letter one Thursday when he noticed that the front door was ajar. Through the opening he could see the man's body lying in a pool of dried blood. When a police officer arrived he surveyed the scene. On the porch were two bottles of warm milk, Monday's newspaper, a catalog, flyers, and unopened mail. The police officer suspects it was foul play. Who does he suspect and why?

Murder Mystery Puzzle

Asked by Neha on 07 Apr 2021

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

Asked by Neha on 02 Jul 2025


Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

Asked by Neha on 04 Oct 2025

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Amazing Facts

Challenging

There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.