143

143 is a natural number that comes after 142 and before 144. In mathematics, it is a semiprime, being the product of the distinct primes 11 and 13 (143 = 11 × 13). It can also be expressed as 12^2 − 1, since it equals (12 − 1)(12 + 1). Its positive divisors are 1, 11, 13, and 143, and its Euler totient is 120.

Representations in other bases include binary 10001111, hexadecimal 0x8F, and Roman numerals CXLIII.

143 is culturally notable for the shorthand message I love you. The digits 1, 4, and 3 are often interpreted as the word lengths of the phrase I (one letter), love (four letters), you (three letters). The idea is used in popular culture and texting as a convenient numeric sign for affection.

Mathematically, 143 is used as an example of a semiprime and of a near-square number. It also serves as a simple case for exploring divisor counts, totients, and modular arithmetic in introductory number theory.