(define positiveInteger?
  (lambda (n)
    (if (not (number? n))    #f
      (if (not (integer? n)) #f 
        (if (< n 1) #f  #t)
      )
    )
  )
) 

;(positiveInteger? 5)       ;#t
;(positiveInteger? 328000)  ;#t
;(positiveInteger? 1)       ;#t
;(positiveInteger? 3+0i)    ;#t
;(positiveInteger? 5.0000000000000001) ;#t
;(positiveInteger? 4.9999999999999999) ;#t
;
;(positiveInteger? 3+1i)    ;#f
;(positiveInteger? 1.1)     ;#f
;(positiveInteger? 0)       ;#f
;(positiveInteger? -5)      ;#f
;(positiveInteger? -1.1)    ;#f
;(positiveInteger? 5.000000000000001) ;#f
;(positiveInteger? 4.999999999999999) ;#f
;(positiveInteger? '())        ;#f  
;(positiveInteger? '(4 5 6))   ;#f 
;(positiveInteger? '(a b))     ;#f