This is the 1153rd most frequent Russian word.
число
"Число" means "number" in English.
'Число' is used here to denote the day's date number.
Сегодняшнее число — первую среду месяца.
Today's date is the first Wednesday of the month.
In this sentence, 'число' refers to a quantity or count of something, here the number of applications.
Число заявок на конференцию увеличилось.
The number of conference applications has increased.
Here, 'число' represents a numeral or an arithmetic entity, specifically a prime number.