The BITAND() function forms the bitwise logical AND of two integer values.
expr1 and expr2 evaluate to integers
The BITAND() function converts expr1 and expr2 to 32 bit integers and performs a bit-by-bit logical AND to form a new integer value as the result.
The value of each bit in the result is 1 if same bit position in both of expr1 and expr2 is 1.
IF BITAND(N, 1) THEN N += 1
This statement adds one to N if the least significant bit is 1. The effect is to round N to an even integer.