140

This number is a composite.

The largest prime factor of 140 is 7. Note that 1² + 2² + 3² + 4² + 5² + 6² + 7² = 140. [Cramer]

The start of a record-breaking run of 7 consecutive integers (140-146) with an even number of prime factors. Note that 7 is the largest prime factor of 140. [Gupta]

(There are 4 curios for this number that have not yet been approved by an editor.)