Zero is the only number that cannot be represented by Roman numerals.
Infinity is a concept rather than a number, representing an endless, boundless quantity.
The golden ratio (φ) is roughly 1.618, commonly found in the proportions of natural objects like shells and flowers.
The Fibonacci sequence (e.g., 0, 1, 1, 2, 3, 5...) exhibits in natural patterns, with each number being the sum of the two preceding ones.
Pi (π) is an infinite, non-repeating decimal, making it an irrational number.
Palindromic numbers read the same backward as forward (121, 1331, 444).