51

This number is a composite.

Just showing those entries submitted by 'Bajpai': (Click here to show all)

The smallest semiprime that is the product of two primes whose concatenation (in some order) produce the decimal expansion of square root of 3, e.g., 51 = 17 *3, 346 = 173 * 2. The sequence begins 51, 346, 8660254037844386465, 9135637898642163233468659, 91356386175449607536090017841537606328361073633, .... . See the largest known. [Bajpai]