September = 9932

First Digit: 9 letter in the spelling of September

Second Digit: September is the ninth month

Third Digit: Number of Vowels in the spelling of September i.e. 3

last digit is square root of there sum of there ranks of alphabets

eg

may: M=13, A=1, Y=25, sum is 49, 4+9=13, 1+3=4: sq root of 4 is 2..

Similarly:

S=19 e=5 p=16 t=20 e=5 m=13 b=2 e=5 r=18

=> total =103=4,

=> sq root of 4 is 2,

=> so overall 9932