Yep! 🧡 - 21 is an odd composite number, composed of two prime numbers multiplied together (3 and 7). - 21 is the sum of the first six natural numbers (1 + 2 + 3 + 4 + 5 + 6 = 21), making it a triangular number. - And 21 is part of the Fibonacci sequence, (0, 1, 1, 2, 3, 5, 8, 13, 21…).