what are the truth behind this 777888999 phone blast

I just dialled this number 2-3 times from my phone using online calling and both simcards

Using first sim card, it's ended without any beep sound within few seconds again I'm call on this number it says "Please check the number you have dialed, this number doesn't exist".
Using second sim card, it says again “please check the number you have dialed, this number doesn't exist”
See “777888999 doesn't exist”

It has only 9 digits, and mobile numbers in India come with 10 digits (except some toll free/ premium numbers)
Even if you add any std code as prefix in 777888999, it will exceed 10 digits
Now see what's the truth behind this hoax?

How is it possible that by receiving a mere call, your phone is prone to blast?
Is there a bomb in your mobile phone, that might get activated with a call?
Never. It's not possible for anyone not in near future that a phone call be able to blast your smartphone.
Why these types of messages surface then? Who are behind these messages?

(1) Social media users. We must verify these things by own before forwarding these to others.
Some media websites. As they are always in search of this type of spicy things, this helps them to gain huge traffic within very less span of time and news channel.

(2) Social media apps. When these things spread through a particular app, people find it necessary/useful to use these apps.
Hope it helps you to analize yourself what these viral numbers/messages are all about.
Be logical and keep others informed about the real things.
Thanks!