This number is a prime.
Add all three consecutive triangular numbers together where the first is odd and the next two are even. In a list of results the 3rd, 5th, 8th, 21st, 34th and 55th are all the largest of a twin prime pair, this one being the largest of the six. Note that 3, 5, 8, 21, 34, and 55 are Fibonacci numbers that are more abundant than any smaller Fibonacci number. [Homewood]