The footballer (soccer) Declan Rice wears the number 41 on his shirt because it was his youth academy exit's first number, when he likely could have a more prestigious 4 or 6 first team number on his shirts.

42 is the answer to life

43 muscles are needed to frown

+44 is the UK phone extension

A .45 ACP is referred to as a “45” for short.

Joe Biden is the 46th president of the USA

Le Chat Fonce: Dreams can be beaten in 47 seconds

49 is a perfect square

50, among many other wonderful facts, is the score you get for a Bullseye in Darts

a number with 52 zeros is 10 quindecillion

The M53 submachine gun was a relatively unsuccessful variant on the Soviet PPSh-41 gun

54 is an r rated movie from 1998 starring Mike Myers

There are 55 spaces on Bowser's Enchanted Inferno! in Mario Party 7.

56 is the sum of the first 6 triangular numbers (1+3+6+10+15+21)

Bad Piggies 2 has 57 levels

California has 58 counties

59 is the chemical element Praseodymium (Pr)

redoing this because old one was bad:

there are 60 minutes in an hour and 60 seconds in a minute