How many LDS missionaries are there?

51,736.

According to statistical information published on the Church of Jesus Christ of Latter-day Saints website, there are 51,736 LDS missionaries world-wide, assigned to 344 different missions. In 36 years, the number of missionaries has nearly tripled. Each missionary usually serves for at least 6 months and at most 24 months; the majority of missionaries are aged under 25 years.