Is this parallel calculation using the new concurrent.futures lib OK?

I submitted the following, which runs OK for me, but I only have a single core machine and I take the documentations comm开发者_运维知识库ent that it will be spread over more cores if I had them; automatically.

from concurrent import futures
import math

NUMBERS = [
    112272537195293,
    112582718962171,
    112272537095293,
    115280098190773,
    115797840077099,
    1099726829285419]

def lowest_factor(n):
    if n % 2 == 0:
        return 2
    sqrt_n = int(math.floor(math.sqrt(n)))
    for i in range(3, sqrt_n + 1, 2):
        if n % i == 0:
            return i
    return n

def main():
    print( 'For these numbers:\n  ' + '\n  '.join(str(p) for p in NUMBERS) )
    with futures.ProcessPoolExecutor() as executor:
        low_factor, number = min( (l, f) for l, f in zip(executor.map(lowest_factor, NUMBERS), NUMBERS) )
        print('    The mnimal prime factor is %d of %i' % (low_factor, number))

if __name__ == '__main__':
    main()

It looks OK to me running in Python 3.2b1 (r32b1:87064, Dec 5 2010, 19:08:18), but I would welcome criticism from others. P.S. I did the above for this: http://rosettacode.org/wiki/Parallel_calculations

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I bought a multi-core laptop for xmas. The example worked fine.