37

37 (thirty-seven) is the natural number following 36 and preceding 38. In mathematics 37 is the 12th prime number, and the 3rd isolated prime without a twin prime. 37 is the first irregular prime. The sum of the squares of the first 37 primes is divisible by 37. Every positive integer is the sum of at most 37 fifth powers (see Waring's problem). It is the third cuban prime following 7 and 19. 37 is the fifth Padovan prime, after the first four prime numbers 2, 3, 5, and 7. It is also the fifth lucky prime, after 3, 7, 13, and 31. 37 is the third star number and the fourth centered hexagonal number. There are exactly 37 complex reflection groups.