在R中求出生存分析中对数正态分布的均值

I am a novice with R. Currently I am fitting a log-normal distribution to some survival data I have, however I have become stuck when trying to calculate statistics such as the median and the mean. This is the code I have used so far, can anyone tell me what I should type next to find the mean?I am a novice with R. Currently I am fitting a