I’m up to volume 4 in Joseph Frank’s 5-volume biography of Dostoevskii and his reading of Crime and Punishment. Without dwelling on it (so far at least), he mentions that the name Raskolnikov “evokes the Russian word for a schismatic religious dissenter, a raskolnik” and the name Razumikhin “contains the Russian word for ‘reason,’ razum” (98–99). Frank says that naming Razumikhin after reason is evidence of “Dostoevsky’s desire to link the employment of this faculty not only with the cold calculations of Utilitarianism but also with spontaneous human warmth and generosity” (99). There’s also an interesting footnote on Dostoevskii accidentally writing Rakhmetov in his notes when he means Razumikhin, and Razumikhin saying that his name is an abbreviation of the original form Vrazumikhin.
It’s a small thing, but I’ve always wondered why everyone explaining “Razumikhin” for an Anglophone audience works from razum. It’s just the -in ending that’s one of the standard endings for Russian surnames (along with -ov/-ev). The -ikh- is something else. To my non-native ear it sounds like the obsolete form razumikh, as in азъ разумихъ. (Is the proper aorist form азъ разумѣхъ? You can find examples of both.) After all, the name could have been Razumov or even Razumin; both exist, and the first is reasonably common. Razumov/Razumin would still have meant reason, and the warm kind of reason instead of the cold rassudok. But Razumikhin has, if I’m not mistaken, the additional suggestion of ecclesiastical language, the Church, and Christianity.