failed_fft_mult

$ python rosetta.py 5000000 | shuf -n2
1099489
4113097

$ calc '1099489*4113097'
4522304907433

$ pypy easy_primes.py -f 4522304907433 -t 1100000 -v
Largest prime 1100009
Searching for factors of 4522304907433 up to 2126572 (except not really)
Previously unfound/unknown prime: 4113097
Successfully found factors: 1099489 * 4113097

$ python3
>>> base64.b16encode(int.to_bytes(4522304907433, length=8, byteorder='big', signed=True))
b'0000041CEE60A8A9'
>>> list(map(int, int.to_bytes(4522304907433, length=8, byteorder='big', signed=True)))
[0, 0, 4, 28, 238, 96, 168, 169]
>>> list(map(int, int.to_bytes(1099489, length=8, byteorder='big', signed=True)))
[0, 0, 0, 0, 0, 16, 198, 225]
>>> list(map(int, int.to_bytes(4113097, length=8, byteorder='big', signed=True)))
[0, 0, 0, 0, 0, 62, 194, 201]

$ python2
>>> from scipy.fftpack import (fft, ifft)
>>> import numpy as np
>>> ifft(np.multiply(fft([0, 0, 0, 0, 0, 16, 198, 225]), fft([0, 0, 0, 0, 0, 62, 194, 201]))).real
array([-7.27595761e-12,  0.00000000e+00,  9.92000000e+02,  1.53800000e+04,
        5.55780000e+04,  8.34480000e+04,  4.52250000e+04, -7.27595761e-12])