how to generate secure random number in php? [duplicate]

This question already has an answer here:

• replace rand() with openssl_random_pseudo_bytes() 6 answers

I was using mt_rand() func. but it is not secure. I want to generate a random number but I don't know how to do it. After some research I have found that openssl_random_pseudo_bytes() func. is generating random string but I just want to generate random number not alphabetic characters. Is there any way to do this?