123 may refer to: . The first three positive Arabic numerals; 123 (number), the natural number following 122 and preceding 124 AD 123, a year of the Julian calendar, in the second century AD; 123 BC, a year of the pre-Julian Roman calendar; Entertainment. 123, a 2002 Indian romantic comedy; 123, 2016 Philippines film by Carlo Obispo at 12th Cinemalaya Independent Film Festival

Iodine-123 (123 I) is a radioactive isotope of iodine used in nuclear medicine imaging, including single-photon emission computed tomography (SPECT) or SPECT/CT exams. The isotope's half-life is 13.22 hours; the decay by electron capture to tellurium-123 emits gamma radiation with a predominant energy of 159 keV (this is the gamma primarily used for imaging). ). In medical …

123（百二十三、ひゃくにじゅうさん）は自然数、また整数において、122の次で124の前の数である。. 性質. 123 は合成数であり、約数は 1、3、41 と 123 である。. 約数の和は168。; 42番目の半素数である。 1つ前は122、次は129。. 121, 122, 123と半素数が3連続する3番目の組合わせ …