No, there's 4 quadrillion units. The 21M is a psyop that doesn't apply, because the units are divisible without losing utility.

If you cut a banana in half, it doesn't full two people the same as a whole banana each. If you cut a tractor in 10 pieces, you don't have the same utility as 10 tractors.

Not so with Bitcoin. A division of a Bitcoin fulfills the same purpose as a whole Bitcoin. It loses no utility on account of it's division.

If you could slice a banana into 100 pieces and each piece still satisfied the same wants as a full banana, you have effectively expanded the supply of whole bananas.

The supply of units on the Bitcoin blockchain will be 4 quadrillion, if we imagine it will never ever change (tho that requires less sign-off than a Fed interest rate hike).