SB 10.50.4
aksauhinibhir vimsatya
tisrbhis capi samvrtah
yadu-rajadhanim mathuram
nyarudhat sarvato disam
Translation:
With a force of twenty-three aksauhini divisions, he laid siege to the Yadu capital, Mathura, on all sides.
Purport:
The numbers involved in an aksauhini division are given in the word meanings. An aksauhini was a standard fighting force in ancient times.