(number theory) perfect number, a positive integer that is equal to the sum of its positive divisors, excluding the number itself

(number theory) deficient number, a number for which the sum of proper divisors is less than that number

(number theory) amicable numbers, two different numbers related in such a way that the sum of the proper divisors of each is equal to the other number.

(Internet) play count

unlucky number

(offensive, Internet slang) Alternative form of 子供部屋おじさん

(offensive, Internet slang) a man whose age is greater than about thirty or forty who lives in one's child room and with one's parent(s).

single room

double room

Synonym of 黄昏 (tasogare, “dusk; twilight”) / Synonym of 黄昏時 (tasogaredoki, “dusk; twilight”)