Mathematically 45

Forty Five (45)

1. It is a Kaprekar number. A number n is called Kaprekar number if n^2 = xy and x + y = n.
45^2 = 2025 and 20 + 25 = 45

2. It is a triangular number.

3. It is the sum of first nine natural numbers. The formula to sum the n natural number is given by – n (n+1)/2. 1 + 2 + 3+ 4 + 5 + 6+ 7 + 8 + 9 = 45

4. It is the sixth positive integer with a prime factorization in the form of p2q, with p and q are primes.
45 = 3^2 x 5

5. The atomic number of Rhodium is 45.

6. It is the 5th hexagonal number that can be obtained using the formula – n(2n – 1). The hexagonal numbers are – 1, 6, 15, 28, 45---

7. It is a name of card game played between two players as two teams. The winner is the first to gain 45points.

8. It can be partitioned in 75175 ways.

9. It is a 16- gonal number.

10. Here is a mystic rose pattern that contains 45 lines. It is drawn by placing 10 marks around a circle and joining them.

Dr Rajesh Kumar Thakur