57

This number is a composite.

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

The smallest April Fools prime that is the sum of first n April Fools primes, i.e., (9 + 21 + 27), (case n=3). [Loungrides]

The smallest double-digit odd number that creates two primes (5657 and 5857) by concatenation with its previous and next even numbers. [Loungrides]