Number 211

Number 211

30th July in a normal year and 31st July in a leap year is the 211th day of the year
1. It is an odd number

2. It is the sum of three consecutive primes.
211 = 67 + 71 + 73

3. It is a Chen Prime. A prime number p is called a Chen prime if p + 2 is either a prime or product of two primes.

Rajesh Kumar Thakur

Number 210

Number 210

1.  (21, 20, 29) and (35, 12, 37) are the two least primitive Pythagorean triangles with different hypotenuses and the same area (=210).

2. It is the product of first four prime number
                         210 = 2 x 3 x 5 x 7

3. It is the sum of 8 consecutive prime numbers.
                   13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 = 210

4. It is a triangular Number. 
                   190              210                    231

5. It is a Harshad Number. To know more about Harshad Number. Harshad number was discovered by Indian Mathematician Kapekar.

6. It is a Pronic Number. Pronic number is a number which is the product of n and n+ 1
                210 = 14 x 15


7. It is an abundant Number. Abundant number is a number whose sum of proper divisor is more than the number. 
12 is the first abundant number.
Factor of 12 are 1, 2, 3, 4 and 6
1 + 2 + 3 + 4 + 6 > 12

8. It is a composite number, even number and pentagonal number.

Dr Rajesh Kumar Thakur