Command line to find prime factors up to about 35-digit
echo 1876356133953640506822053967773074005663647709224374242959845441038980287292994105040158088923184539551392048889349169561984324490547319339771678501378682355721969287530319310154004137674806383 | ecm -n -c 825 1e6
Command line to find prime factors up to about 40-digit
echo 1876356133953640506822053967773074005663647709224374242959845441038980287292994105040158088923184539551392048889349169561984324490547319339771678501378682355721969287530319310154004137674806383 | ecm -n -c 2336 3e6
Command line to find prime factors up to about 45-digit
echo 1876356133953640506822053967773074005663647709224374242959845441038980287292994105040158088923184539551392048889349169561984324490547319339771678501378682355721969287530319310154004137674806383 | ecm -n -c 4479 11e6
Command line to find prime factors up to about 50-digit
echo 1876356133953640506822053967773074005663647709224374242959845441038980287292994105040158088923184539551392048889349169561984324490547319339771678501378682355721969287530319310154004137674806383 | ecm -n -c 7553 43e6