68

While 69 often gets the attention, mathematicians and number theorists find 68 far more compelling for several reasons.

, 68 is the very last two-digit number to appear for the first time. While 69 often gets the attention, mathematicians and

In restaurant slang, "68" is the opposite of "86" (which means to remove an item from the menu). A "68" means an item is back on the menu or available. A "68" means an item is back on the menu or available

It is known as the largest number that can be expressed as the sum of two primes in exactly two different ways ( Many mathematicians believe it is the last even

), a regular 68-sided polygon is considered constructible using only a compass and straightedge. 68 in Culture and Daily Life

). Many mathematicians believe it is the last even number to have this exact property before higher numbers begin having three or more pairs. Because of its factorization (

On an infinite chessboard, there are 68 distinct squares that are exactly three knight's moves away from any starting square.