41

41 is the integer preceeding 42 and succeeding 40.

Properties:
 * 41 is a prime number
 * 41 is a value of n such that x^2 + x + n takes on prime values for all x = 0, 1, 2, ... n-2
 * 41 is the 5th centered square number
 * the digital root of 41 is 5