"My father," said Mrs. King, "a professor of botany, had a rather endearing quirk: he could memorize historical dates and telephone numbers--for example our number 9743--only insofar as they contained primes. In our number he remembered two figures, the second and last, a useless combination; the other two were only black gaps, missing teeth."
"Oh, that's good," cried Audace, genuinely delighted. (4.4)

The second and last figures in the Kings's telephone number seem to hint at seven and three, the two of Hermann's three cards in Pushkin's Pikovaya dama ("The Queen of Spades"). The sum of two remaining figures (9 + 4 = 13) makes devil's dozen (another prime). The devils (and the apocalyptic number 666) appear in "The Secluded Small House in the Vasilievski Island", a story published by V. Titov and discussed by Hodasevich in "Pushkin's St. Petersburg Tales". (In "The St. Petersburg Tales" authored by Pushkin supernatural forces are also at work acting covertly.)

While Vadim's friend, the poet Audace seems to be an American version of Hodasevich, Mrs. King's name may hint at a playing-card. Mrs. King's father was a professor of botany. In Pushkin's "The Queen of Spades" troika (three) blooms before Hermann in the forms of a magnificent grandiflora flower. In the madhouse Hermann "sits" in ward 17 (yet another prime).

In Paris Vadim glimpses the parturition of a new literary review, Prime Numbers (2.4). Prostye chisla (prime numbers) bring to mind Prostakov-Skotinin ("simpleton and brute"), as Hristofor Boyarski calls a fellow critic (1.11). The son of Mme Prostakov (born Skotinin), Mitrofan is the main character in Fonvizin's comedy Nedorosl' ("The Minor", 1782). Belvederskiy Mitrofan is mentioned by Pushkin in his epigram "Luk zvenit, strela trepeshchet..." ("The Bowstring sounds, the arrow quivers..." 1827) Belvederskiy has Bel (Vadim's name for his daughter Isabel) in it.