$\sum_{n=1}^{\infty} n $ equals to another value than $\frac1{12}$

Question

clearly $\sum_{n=1}^{\infty} n $ is a divergent series

but there is a way to show that $\sum_{n=1}^{\infty} n =-\frac1{12}$ (not really meaningful to me)

My problems are,

1. can we show $\sum_{n=1}^{\infty} n $ is equal to another real number different from $-\frac1{12}$ ?

2. If there is a way, by using these results can we prove the series $\sum_{n=1}^{\infty} n $ is divergent?(using the method of contradiction)

thanks.