Um, I don't think the meaning of this name is correct. I only know basic Japanese so I could be wrong, but one is ichi (いち), two is ni (に), and three is san (さん). The kanji used for the name is correct (一 ニ 三), and is usually read as the numbers but it could have different meanings, as a single kanji can have multiple meanings.
Japanese has another numeral in ancient language which is called yamato-kotoba.Number/Japanese/ancient-Japanese 1/ ichi/ hi 2/ ni/ fu 3/ san/ mi 4/ yon/ yo 5/ go/ itsu 6/ roku/ mu 7/ shichi/ nana 8/ hachi/ ya 9/ kyuu/ koko 10/ juu/ too 100/ hyaku/ momo 1000/ sen/ chi 10000/ man/ yorozuBy the way, there is consonant association between double numbers. 1hi-2fu(hu), 3mi-6mu, 4yo-8ya, 5(i)tsu-10too. It is said that is because people counted with two hands. Then 7 nana is for not abreast (naraba nai), koko is for bent (finger) (kagamu).