166666666

166666666 is a natural number. It lies between 166666665 and 166666667, and it is often noted for its distinctive decimal pattern: one followed by eight sixes.

In decimal notation, the number is written as 1 and then eight 6s, producing a highly recognizable repdigit-like sequence with a single different leading digit. This pattern makes it a simple example in discussions of digit parity, repetition, and decimal representation.

Mathematical properties include its parity and basic divisibility. 166666666 is even, so it is divisible by 2, with a quotient of 83333333. The digit sum is 49, which is not a multiple of 3, so the number is not divisible by 3. It is also not divisible by 5 or 11, based on standard divisibility rules. The initial factorization is 2 × 83333333; the odd factor 83333333 is itself not divisible by small primes such as 3 or 5, and its complete factorization would require further testing. Beyond this, no widely notable mathematical constants or identities are directly associated with 166666666.

In usage, numbers with long runs of the same digit or a simple leading digit are often used in educational examples, data formatting tests, or as illustrations of digit-pattern behavior in arithmetic.

See also: repdigit, decimal notation, large numbers.