# 66 (number)

66 (sixty-six) is the natural number following 65 and preceding 67.
 Cardinal 66sixty-six Ordinal 66thsixty-sixth Factorization Divisors 1, 2, 3, 6, 11, 22, 33, 66 Roman numeral LXVI Binary 1000010 Hexadecimal 42

## In mathematics

66 is a sphenic number, a triangular number, a hexagonal number, and a semi-meandric number. Being a multiple of a perfect number, 66 is itself a semiperfect number.

## In sports

The last Packer to wear number 66 before it was retired in 1983 to honor Nitschke was offensive tackle Larry Pfohl who is better known to pro wrestling fans as Lex Luger.

## In Computers

• 66 (more specifically 66.667) Megahertz (MHz) is a very common divisor for the Front side bus (FSB) speed, Overall Central processing unit (CPU) speed, and base bus speed. On a Core 2 CPU, and a Core 2 Motherboard, the FSB is 1066MHz (~16 x 66MHz), the memory speed is usually 666.67MHz (~10 x 66MHz), and the processor speed is ranges from 1.86 Gigahertz (GHz)(~66MHz x 28) to 2.93 GHz (~66MHz x 44), in 266Mhz (~66MHz x 4) increments.

## In other fields

Sixty-six is:
Route 66 sign
1. 1066 – Norman conquest
2. 1666Great Fire of London
3. 1966England win the World Cup

## In Anime

• In Full Metal Alchemist elusive villain Barry the Chopper is imprisoned in cell number 66, which later becomes his alias when battling the brothers at Laboratory Five.

## Historical years

66 A.D., 66 B.C., 1966, 2066, etc.
In mathematics, a natural number can mean either an element of the set (i.e the positive integers or the counting numbers) or an element of the set (i.e. the non-negative integers).
65 (sixty-five) is the natural number following 64 and preceding 66.

## In mathematics

Sixty-five is an octagonal number. It is also a Cullen number. Given 65, the Mertens function returns 0.
67 (sixty-seven) is the natural number following 66 and preceding 68. It is an odd number.

## In mathematics

Sixty-seven is the 19th prime number (the next is 71), an irregular prime, a lucky prime, and the sum of five consecutive primes (7 + 11 + 13 + 17
59 (fifty-nine) is the natural number following 58 and preceding 60.

## In mathematics

Fifty-nine is the 17th smallest prime number. The next is sixty-one, with which it comprises a twin prime.
60 (sixty) is the natural number following 59 and preceding 61. Being thrice twenty, 60 is called "three score" in some older literature.

## In mathematics

Sixty
61 (sixty-one) is the natural number following 60 and preceding 62.

## In mathematics

It is the 18th prime number. The previous is 59, with which it comprises a twin prime. Sixty-one is a cuban prime of the form .
62 (sixty-two) is a natural number following 61 and preceding 63.

## In science

• The atomic number of samarium, a lanthanide

## In mathematics

Sixty-two is a composite number with divisors 2 and 31. It is a nontotient.
63 (sixty-three) is a natural number following 62 and preceding 64.

## In mathematics

Although a number of the form 2n - 1, 63 is not a Mersenne prime since n is not prime and 63 is certainly not prime either.
64 (sixty-four) is the natural number following 63 and preceding 65.

## In mathematics

Sixty-four is the square of 8, the cube of 4, and the sixth power of 2. It is the smallest number with exactly seven divisors.
65 (sixty-five) is the natural number following 64 and preceding 66.

## In mathematics

Sixty-five is an octagonal number. It is also a Cullen number. Given 65, the Mertens function returns 0.
67 (sixty-seven) is the natural number following 66 and preceding 68. It is an odd number.

## In mathematics

Sixty-seven is the 19th prime number (the next is 71), an irregular prime, a lucky prime, and the sum of five consecutive primes (7 + 11 + 13 + 17
68 (sixty-eight) is the natural number following 67 and preceding 69

## In mathematics

Sixty-eight is a nontotient. It is also a Perrin number, preceded in the sequence by 29, 39, 51 (it is the sum of the first two mentioned). It is also a Happy number.
69 (sixty-nine) is a number following 68 and preceding 70.

## In mathematics

• Adding up the divisors of 1 through 9 gives 69.
• Because 69 has an odd number of 1s in its binary representation, it is sometimes called an "odious number"

70 (seventy) is the natural number following 69 and preceding 71. The French do not have a word for 70, instead using "soixante-dix" (60 + 10). Other French-speaking countries such as Belgium and Switzerland do have a word for it, using "septante.

## Rational numbers

### Notable rational numbers

#### Natural numbers

0 1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28 29
30 31 32 33 34 35 36 37 38 39
The integers (from the Latin integer, which means with untouched integrity, whole, entire) are the set of numbers including the whole numbers (0, 1, 2, 3, …) and their negatives (0, −1, −2, −3, …).
0 (zero) is both a number and a numerical digit used to represent that number in numerals. It plays a central role in mathematics as the additive identity of the integers, real numbers, and many other algebraic structures.
10 (ten) is an even natural number following 9 and preceding 11.

0

30 (thirty) is the natural number following 29 and preceding 31.

## In mathematics

It is a primorial as well as the sum of the squares of the integers 1, 2, 3 and 4. It is the smallest Giuga number.
40 (forty) is the natural number following 39 and preceding 41.

Despite being related to the word "four" (4), 40 is spelled as "forty", not "fourty". The letters of the word "forty" are in alphabetical order; this is the only number that has this linguistic property
50 (fifty) is the integer following 49 and preceding 51.
(the number fifty derives from the two numerical figures of both 0 and 5 placed in order from greatest to least)

## In mathematics

Fifty
60 (sixty) is the natural number following 59 and preceding 61. Being thrice twenty, 60 is called "three score" in some older literature.

## In mathematics

Sixty
70 (seventy) is the natural number following 69 and preceding 71. The French do not have a word for 70, instead using "soixante-dix" (60 + 10). Other French-speaking countries such as Belgium and Switzerland do have a word for it, using "septante.
80 (eighty) is the natural number following 79 and preceding 81.

## In mathematics

The sum of Euler's totient function φ(x) over the first sixteen integers is 80.

Adding up some subsets of its divisors (e.g.
90 (ninety) is the natural number preceded by 89 and followed by 91.

## In mathematics

90 is the sum of the squares of the integers 2 to 6. Because 90 is the sum of its unitary divisors (excluding itself), it is a unitary perfect number, and because it is equal
100 (one hundred) (the Roman numeral is C for centum) is the natural number following 99 and preceding 101.

## In mathematics

One hundred is the square of 10 (in scientific notation it is written as ).