Date 1 = 1721027 in the Julian calendar
Date 2 = 2459505 in the Julian calendar
Difference (age) = 738478
If we're looking at biorhythms, the 23 day cycle is the physical cycle.
Day into cycle 1 (23 days) = 17
Start of next cycle = 23rd October 2021
The 28 day cycle is the emotional cycle and can correspond to the menstrual cycle in women. If you are using this calculator for such purposes, you should note that the most likely time for egg fertilisation occurs between days 12 and 17 (assuming the cycle is 28 days). If you change the length of the cycle, this is indicated by danger days.
Day into cycle 2 (28 days) = 6 (danger days = 12 to 17)
Start of next cycle = 8th November 2021
Lastly, the 33 day cycle is known as your intellectual cycle.
Day into cycle 3 (33 days) = 4
Start of next cycle = 15th November 2021