111000111

111000111 is a nine-digit decimal numeral that reads the same forwards and backwards, making it a palindrome. The sequence consists of three ones, three zeros, and three ones in that order, and it is often cited as a simple example of a decimal palindrome rather than as a number with a special mathematical identity.

As a decimal value, it is 111,000,111. The sum of its digits is 6, so the number is divisible by 3. Its prime factorization is 3 × 37 × 101 × 9901, since 111000111 equals 111 × 1,000,001 and 1,000,001 factors as 101 × 9901. This confirms its compositeness and shows a nontrivial factor structure.

If interpreted as a binary numeral, the string 111000111₂ corresponds to the decimal value 455, since 1×2^8 + 1×2^7 + 1×2^6 + 0×2^5 + 0×2^4 + 0×2^3 + 1×2^2 + 1×2^1 + 1×2^0 = 455. In binary it is also a palindrome, mirroring the decimal symmetry in a different base.

In mathematics and computer science, 111000111 is used as a straightforward example of palindromic numbers, base conversion, and simple factorization. It does not denote a widely recognized constant or sequence but serves as an accessible case study for topics including divisibility rules, prime factorization, and numeral systems.

See also Palindrome, Decimal palindrome, Binary number, Factorization.