78 (number) facts for kids
Quick facts for kids



Cardinal  seventyeight  
Ordinal  78th (seventyeighth) 

Factorization  2 × 3 × 13  
Divisors  1, 2, 3, 6, 13, 26, 39, 78  
Greek numeral  ΟΗ´  
Roman numeral  LXXVIII  
Binary  1001110_{2}  
Ternary  2220_{3}  
Senary  210_{6}  
Octal  116_{8}  
Duodecimal  66_{12}  
Hexadecimal  4E_{16} 
78 (seventyeight) is the natural number. It comes between seventyseven and seventynine, and is an even number.
Contents
In mathematics
78 is:
 the dimension of the exceptional Lie group E_{6} and several related objects.
 a sphenic number, having 3 distinct prime factors.
 an abundant number with an aliquot sum of 90.
 a semiperfect number, as a multiple of a perfect number.
 the 12th triangular number.
 a palindromic number in bases 5 (303_{5}), 7 (141_{7}), 12 (66_{12}), 25 (33_{25}), and 38 (22_{38}).
 a Harshad number in bases 3, 4, 5, 6, 7, 13 and 14.
 an Erdős–Woods number, since it is possible to find sequences of 78 consecutive integers such that each inner member shares a factor with either the first or the last member.
77 and 78 form a RuthAaron pair.
In science
 The atomic number of platinum.
In other fields
78 is also:
 In reference to gramophone records, 78 refers those meant to be spun at 78 revolutions per minute. Compare: LP, 33 ^{1}⁄_{3} and 45 rpm. 33 + 45 = 78
 A typical tarot deck containing the 21 trump cards, the Fool and the 56 suit cards make up 78 cards
 The Rule of 78s is a method of yearly interest calculation
See also
In Spanish: Setenta y ocho para niños
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78 (number) Facts for Kids. Kiddle Encyclopedia.