or GNU CLISP which not only has big ints, big ratios, big complex (like all Common Lisp implementations), but also big floats.

Big ratios:

    [2]> (/ 5723475972349572938475982734985723984759823749587 7239457928374598723984759237459723497598234)
    5723475972349572938475982734985723984759823749587/7239457928374598723984759237459723497598234

Big complex numbers:

    [4]> (* 572934759237495723482374957239475982374957239847523485 (sqrt -1))
    #C(0 572934759237495723482374957239475982374957239847523485)

Big float numbers:

    [8]> (SETF (EXT:LONG-FLOAT-DIGITS) 1000)
    1000
    [9]> (sqrt 2.0l0)
    1.4142135623730950488016887242096980785696718753769480731766797379907324784621070388503875343276415727350138462309122970249248360558507372126441214970999358314132226659275055927557999505011527820605714701095599716059702745345968620147285174186408891986095523292304843087143214508397626036279952514079896872534L0