On grammatical class:

ci'i
digit/number: infinity; followed by digits => aleph cardinality.
ka'o
digit/number: imaginary i; square root of -1.
no'o
digit/number: typical/average value.
pai
digit/number: pi (approximately 3.1416...).
te'o
digit/number: exponential e (approx 2.71828...).
tu'o
null operand (used in unary mekso operations).
xo
digit/number: number/digit/lerfu question.