忆起 is more literary than the everyday
想起 (xiǎngqǐ, to recall). The
忆 morpheme is heavier and more poetic — same root as in
回忆 (huíyì, memories) and
追忆 (zhuīyì, to reminisce). For ordinary spoken 'I just remembered…', use
想起来 /
想起 instead; reserve
忆起 for written or reflective contexts.