Mathematically 39

Thirty Nine (39)

1. It is the sum of five consecutive prime numbers.
39 = 3 + 5 + 7 + 11 + 13

2. It is the product of two odd primes.

39 = 3 x 13

3. It can be partioned in 26015 ways.

4. It is the sum of 10th odd and 10th even number.
39 = 19 + 20

5. It is the sum of first three powers of 3.
39 = 3^1+ 3^2 + 3^3

6. It is the sum of numbers 4 through 9.
39 = 4 + 5 + 6 + 7 + 8 + 9

7. It is the sum of 6th, 7th and 8th odd numbers.
11 + 13 + 15 = 39

8.It (39) is the smallest number with multiplicative persistence 3. [Multiplicative persistence is the number of times the digits must be multiplied until they produce a one digit number; 3(9)= 27; 2(7) = 14; 1(4)=4. ] - 

9. The F26A graph is a symmetric graph with 39 edges. In graph theory, the F26A graph is a symmetric bipartite cubic graph with 26 vertices and 39 edges.

10. It is equal to the number of plus (+) signs needed to write the partitions of 7.

11. It is the smallest natural numbers which has 3 partitions into three parts (25, 8, 6), (24, 10, 5) and (20, 15, 4)-which all give the same product when multiplied.

12. It is a 14- gonal number or Tetradecagonal number. The formula to obtain a 14 gonal number is ½ (12n^2 – 10n).

13. The largest Armstrong number in decimal numbers has 39 digits. (115,132,219,018,763,992,565,095,597,973,522,401 is the largest)

A number is called Armstrong number if it can be expressed as the sum of the its own digits , each raised to the power  of the number of digits of the number. It is also called Narcissistic number.

There are just four numbers, after unity, which are the sums of the cubes of their digits: , , , and 407 = 4^ 3 + 0^3 + 7^3

Dr Rajesh Kumar Thakur
rkthakur1974@gmail.com