"Everything seems completely different. The feeling is yet to sink in. I had never thought I would be able to win Rs. 5 crore, " Kumar, 27, told on phone from Mumbai.
This was Kumar's second attempt at making it to the hot seat which turned into a life-changing moment for him - he entered the show with the aim of winning Rs. 2, 500, 000. He won 20 times that.
"I came to the show with the mindset that I would go back home with at least Rs. 25, 00, 000 but by god's grace I have won Rs. 5 crore. Even after deducting the tax, I know I would get at least Rs. 3. 5 crore which is enough for me, " he said.
Before becoming a crorepati, Kumar, who hails from East Champaran in Bihar, used to work as a computer operator. So winning the game show is a big moment in his life.
"Ever since I have won, I am stormed with calls from family and friends and even from those whom I have rarely met. It's a fabulous feeling. I didn't prepare much for the show. I just had an idea of what could be asked and did a little preparation with whatever books I had, " he said.
Kumar, who is married, lives in a big joint family - he has five brothers, five nieces and a nephew.
"First of all, I would build my new house. Then my younger brother is working with a garment shop and earns merely Rs. 1, 500 per month. I would help him to start a new business so that he gets settled in life. I am also planning to help my elder brother to get a new shop, " he added.
An MA in psychology, Kumar wanted to appear for the civil services examination, but the financial crunch didn't allow him to pursue his dreams.
"I had so many dreams, but my financial condition didn't allow me to pursue them; hence I stopped dreaming. I got a job where I could earn Rs. 6, 000 per month and was satisfied as I had responsibilities over my shoulder.
"Now I have enough money to help my family as well as fulfil my dream. I am now planning to go to Delhi to prepare for the exam, " he added.
Asked about his family's reaction, Kumar said: "Although it is Diwali, they are celebrating it like Holi. A lot of people are coming down to my house to congratulate my family. "
"There's a perception that people from Bihar are not as well-versed as people of other states; so whenever somebody achieves something big, it becomes celebration time for everyone. Everybody is very proud of my achievement, " he added.
Kumar is all praise for host Amitabh Bachchan. "I was quite nervous when I made it to the hot seat, but his love and affection calmed me down and my nervousness vanished completely. "