1133 (number)

1133 is a four‑digit natural number notable for being a semiprime (11 × 103) and a Blum integer. This article summarizes its arithmetic properties, representations, and common contexts of use.

Overview

1133 is a natural number that follows 1132 and precedes 1134. As an integer it appears in arithmetic, number theory, and as a label in calendars, addresses, and identifiers. Written in Roman numerals it is MCXXXIII.

Basic arithmetic properties

1133 is a composite number whose prime factorization is 11 × 103, so it is a semiprime (the product of exactly two primes). Because both prime factors are congruent to 3 modulo 4 (11 ≡ 3, 103 ≡ 3), 1133 is also a Blum integer, a class of numbers sometimes used in cryptographic constructions. Its positive divisors are 1, 11, 103 and 1133; the sum of proper divisors is 115, which is less than 1133, so the number is deficient.

Representations and tests

Decimal: 1133
Binary: 10001110101
Hexadecimal: 46D
Octal: 2155
Roman numerals: MCXXXIII

Simple divisibility checks apply: alternating digit sum (1−1+3−3 = 0) confirms divisibility by 11. Because both prime factors are 3 mod 4, 1133 cannot be expressed as a sum of two integer squares.

Contexts and notable facts

Numbers like 1133 commonly serve as years (AD 1133), street numbers, product or model identifiers, and entries in enumerations. In mathematics, its status as a semiprime and as a Blum integer gives it interest in elementary number theory and in introductory discussions of cryptographic building blocks. Beyond these contexts it has no widely recognized special properties such as being a perfect power, a factorial, or a figurate number.