"The mystery behind number 13"

We are told that 13 is an unlucky number. The number 13 is associated with bad luck in some countries,

and even has a specifically recognized phobia, Triskaidekaphobia.

Theory as to why the date and number 13 is considered unlucky is that, The date Friday the 13th is taboo because the Knights Templar were arrested and condemned by the seneschals of Philippe IV, King of France, in a “pre-dawn raid” on Friday, October 13th, 1307. The number 13 has been shunned for centuries. Some architects omit the 13th floor from office buildings to this very day. 

The number 13 has always been associated with magic and the occult, and it is a number perceived to possess some mysterious yet tangible power. It is an emblem of a secret knowledge, a knowledge which does indeed confer power upon those conversant with it.

As per hindu astrology, it is considered auspicious to name a baby girl on the 13th day after her birth.

As per Sikhism, the number 13 is considered a special number since 13 is tera in Punjabi, which also means “yours” (as in, “I am yours, O Lord”). The legend goes that when Guru Nanak Dev was taking stock of items as part of his employment with a village merchant, he counted from 1 to 13 (in Punjabi) as one does normally; and thereafter he would just repeat “tera”, since all items were God’s creation. The merchant confronted Guru Nanak about this, but found everything to be in order after the inventory was checked. April 13 also usually turns out to be Vaisakhi every year, which is the Sikh New Year and the major Sikh Holiday.