even, composite, perfect square, palindrome · 4th positive integer

The number 4

4 is an even composite number. It's known as the smallest composite number. It is the 4th positive integer.

Quick reference

Prime factorization	2 × 2
Divisors	1, 2, 4
Binary	100
Hexadecimal	0x4
Roman numeral	IV
Digit sum	4
Properties	even, composite, perfect square, palindrome

Why 4 is notable

The smallest composite number.

Reading 4 in NumGrid context

The 4 record above pulls directly from classical number theory plus NumGrid solver-derived puzzle statistics. What follows is the per-entity context — how 4 sits in the broader integer properties and number-guessing puzzles distribution and which underlying factors drive the headline numbers.

The methodology behind every numeric value on this page is publicly documented on the classical number theory plus NumGrid solver-derived puzzle statistics portal and described in detail on this site’s methodology page. Refresh cadence varies by underlying series; the page surfaces the as-of date for each number so readers can trace any figure back to the source release.

For readers using this page as a decision input, the related-entity pages elsewhere on the site provide the comparison set. The most useful comparison for 4 is typically a peer within positive integers within the NumGrid target pool with similar size, similar exposure, or similar geography — not the national-level summary alone.