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.
Frequently asked
Is 4 a prime number?
No. 4 is composite. Its prime factorization is 2 × 2.
What are the factors of 4?
The factors (divisors) of 4 are 1, 2, 4.
What is 4 in binary?
4 in binary is 100. In hexadecimal it's 4.
What is 4 as a Roman numeral?
4 in Roman numerals is IV.
What's the digit sum of 4?
Adding the digits of 4: 4 = 4.