About the Number 78 (seventy-eight)

MathBabbler created a nBAB for the number 77 on 29 March 2009. While working on that nBAB, he learned that 77 was a Ruth-Aaron pair with 78. On 31 March 2009, MathBabbler and his CSC100 class wrote a C program that determines if a number is a member of the Ruth-Aaron pair. This nBAB about the number 78 is the first nBAB to use the MBNA's Ruth-Aaron program.

   MathBabbler Number Analyst (MBNA) output:
   =========================================
   78 is a natural, whole, integer
   78 is even
   78 proper divisors are: 1,2,3,6,13,26,39,
   78 is abundant (sum of divisors is 90)
   78 is unhappy
   78 is not a Harshad number
   78 is not prime
   78 has the prime factors: 2*3*13
   78 is sphenic (had 3 unique prime factors)
   78 sum prime factors: 2...3...13...answer: 18
   78 is undulating
   78 and 77 are a Ruth-Aaron pair
   78 and 77 are a Ruth-Aaron pair (distinct prime factors)
   78 in octal is 0116
   78 in hexadecimal is 0x4e
   78 in binary is 1001110 (is evil)
   78 nearest square numbers: -14...3 (64...81 [9])
   sqrt(78) = 8.83176
   ln(78) = 4.35671
   log(78) = 1.89209
   78 reciprocal is .01282051282051282051282051282051
   78! is 1.13243e+115
   78 is 24.8282 Pi years
   78 is 3 score and 18 years
   78 written as a Roman numeral is LXXVIII

[Wikipedia] 78 is a triangular number. A triangular number is the "number of dots in an equilateral triangle evenly filled with dots. For example, three dots can be arranged in a triangle; thus three is a triangle number."

On 2 April 2009, when this nBAB was created, the MBNA was not checking from triangular numbers.

OEIS.org::id:A000217

Update::2009.10.04

Pavel Popovich, the 6th man to orbit Earth, died on 29 September 2009 at the age of 78.

log4(78) approximates Pi rounded to the nearest hundredth.

7813 equals repdigit number 99.

BAB created on 4 October 2009... BAB::Pavel Popovich is Dead at 78

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 02 April 2009