Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_27653752_1 ( ppi__pixels_per_inch__ VARCHAR, ppcm__pixels_per_cm__ VARCHAR )

### Question ###
How many different PPI does the model with ppcm of 87 have?

### Accurate SQL ###

SELECT COUNT(ppi__pixels_per_inch__) FROM table_27653752_1 WHERE ppcm__pixels_per_cm__ = 87