# 45 (number): Wikis

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# Encyclopedia

45
Cardinal forty-five
Ordinal 45th
(forty-fifth)
Factorization $3^2 \cdot 5$
Prime 1, 3, 5, 9, 15, 45
Roman numeral XLV
Binary 1011012
Octal 558
Duodecimal 3912

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 p2q, 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 452 + 1 = 2026 is 1013, which is clearly more than 45 twice, 45 is a Størmer number.

The sum of all the digits is 45 (1+2+3+4+5+6+7+8+9=45)

Also The number forty-five is pronounced 4T5 easy huh

## In music  45 rpm gramophone record

## In other fields

Forty-five may also refer to:

## Historical years

45 A.D., 45 B.C., 1945, 2045, etc.

# Simple English

Forty-five is a number. It comes between forty-four and forty-six, and is an odd number. It is divisible by 3, 5, 9 and 15.