+'

(+')
;;=> 0

(+' 1)
;;=> 1

(+' -10)
;;=> -10

(+' 1 2)
;;=> 3

(+' 1 2 3)
;;=> 6

(apply + (range 10000000000000 10000000001000))
;; ArithmeticException: integer overflow

(apply +' (range 10000000000000 10000000001000))
;;=> 1000000000499500

(class 1)
;; => java.lang.Long

(+ 1 Long/MAX_VALUE)
;; => java.lang.ArithmeticException: integer overflow
;;        Numbers.java:1388 clojure.lang.Numbers.throwIntOverflow
;;        Numbers.java:1687 clojure.lang.Numbers.add

(+' 1 Long/MAX_VALUE)
;; => 9223372036854775808N

(class (+' 1 Long/MAX_VALUE))
;; => clojure.lang.BigInt