45 (
forty-five) is the
natural number following
44 and followed by
46.
In mathematics
Forty-five is a
triangular number, a
hexagonal and 16-
gonal number, a
Kaprekar number, and a
Harshad number.
45 is the sixth
positive integer
with a
prime factorization of
the form
p^{2}q, with
p and
q being
prime.
33 is the
aliquot sum of 45 and the
aliquot sequence of 45 is
(45,33,15,9,4,3,1,0).
Since the greatest prime factor of 45
^{2} + 1 = 2026 is
1013, which is clearly more than 45 twice, 45 is a
StÃ¸rmer number.
The sum of all the digits is 45 (1+2+3+4+5+6+7+8+9=45)
In science
Astronomy
In music
In other fields
Forty-five may also refer to:
Historical years
45 A.D.,
45
B.C.,
1945,
2045,
etc.