63 (
sixty-three) is a
natural number following
62 and preceding
64.
In mathematics
Although a number of the form 2
^{n} - 1, 63 is not a
Mersenne prime since n is not
prime and 63 is certainly not prime
either. It is a
Woodall number and a
Harshad number. It is a
highly cototient number. It is a
repdigit in base 4 (333). 63 is weak
(63+36=99), but
64 is very strong.
In science
Astronomy
In other fields
Sixty-three is:
In sports
Historical years
63 B.C.,
63
A.D.,
1963,
2063, etc.