43 (number) This article is about the number 43. For the year, see 43. Forty-three is a number. It comes between forty-two and forty-four, and is an odd number. It is also the 14th prime number, after 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, and 41. This short article about mathematics can be made longer. You can help Wikipedia by adding to it.