Let’s look for the numbers in Mayan language(s)
Bar-and-dot numerals
The author of the book “2000 Years of Mayan Literature” (1) has chosen to translate bar-and-dot numerals with their Arabic equivalents. The numerals constructed with bars and dots range from 1 to 19:

Bars-and-dots are used in combination with signs for zero
When numbers modify nouns, they are usually prefixed in a vertical position, but they can also be written horizontally in which case the dots go above the bars.
The numbers from 1 to 19 are constructed with bars and dots. Zero is marked as a sign
The number 13
The number thirteen has a significant importance in Mayan calendar and in a measure of time. For example, if measuring from the first appearance of a crescent to a full moon – it will consist thirteen days.

If calculating all major points in a human body (knees, hips, wrists, elbows, shoulders and neck) – that is thirteen too.
While the number of fingers and toes is twenty, and 20 x 13 = 260. By Mayan calculation, the number of 260 days is considered as an ideal interval between the diagnosis of a pregnancy and the birth of a child.
References:
- KOBA, K., et al. Antibacterial Activities of the Buds Essential Oil of Syzygium Aromaticum (L.) Merr. & Perry from Togo. Journal of Biologically Active Products from Nature, 2011, vol. 1, no. 1. pp. 42-51.
- How Drinking Grapefruit Juice Could Increase Your Cervical Mucus by Lindsay Meisel, 2017, online source: https://www.avawomen.com/avaworld/grapefruit-juice-cervical-mucus/
- How to Increase Your Fertility by Janet Stephens, book’s online source: https://books.google.pl/books?hl=en&lr=&id=hXrgDwAAQBAJ&oi=fnd&pg=PP11&dq=grapefruit+juice+fertility+cervical+mucus&ots=h-9d6b_M9k&sig=TjAHHTFK7GS9lKCLxW-OKhDQnbA&redir_esc=y#v=onepage&q=grapefruit%20juice%20fertility%20cervical%20mucus&f=false
2000 Years of Mayan Literature By Dennis Tedlock, University of California Press, Jan 19, 2010, available online:
https://books.google.pl/books?id=_6swDwAAQBAJ&pg=PA155&lpg=PA155&dq=two+seated+men,+marked+as+literate+by+the+pens+in+their+headbands&source=bl&ots=iXoryLyj4L&sig=ACfU3U174ZJJVmD1lHDyXwLwTjM3W7CLkQ&hl=en&sa=X&ved=2ahUKEwishOXjltLrAhXD_KQKHfKwBBAQ6AEwAHoECAEQAQ#v=onepage&q=two%20seated%20men%2C%20marked%20as%20literate%20by%20the%20pens%20in%20their%20headbands&f=falsePhoto(s) / drawing(s) by Dr. A. Palatronis on www.z-antenna.com