553 = 7 x 79.
553 is a rhombic dodecahedral number.
553 is the sum of nine consecutive primes: 553 = 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79.
Inserting a zero between adjacent digits of 553 produces a prime: 50503.
The CN Tower in Toronto is about 553 meters tall.
