78
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 168
- Proper Divisor Sum (Aliquot Sum)
- 90
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 24
- Möbius Function
- -1
- Radical
- 78
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- yes
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 35
- Smith Number
- no
Classification
- Natural
- yes
- Even
- yes
- Odd
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Names
- German
- achtundsiebzig· ordinal: achtundsiebzigste
- English
- seventy-eight· ordinal: seventy-eighth
- Spanish
- setenta y ocho· ordinal: 78º
- French
- soixante-dix-huit· ordinal: soixante-dix-huitième
- Italian
- settantotto· ordinal: 78º
- Latin
- septuaginta octo· ordinal: 78.
- Portuguese
- setenta e oito· ordinal: 78º
Appears in sequences
- Number of series-reduced trees with n nodes.at n=14A000014
- Coefficients of the 3rd-order mock theta function f(q).at n=27A000025
- Let k = p_1^e_1 p_2^e_2 p_3^e_3 ... be the prime factorization of n. Sequence gives k such that the sum of the numbers of 1's in the binary expansions of e_1, e_2, e_3, ... is odd.at n=36A000028
- Number of necklaces with n beads of 2 colors, allowing turning over (these are also called bracelets).at n=10A000029
- Numbers that are not squares (or, the nonsquares).at n=69A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=57A000052
- Positive zeros of Bessel function of order 0 rounded to nearest integer.at n=24A000134
- Number of partitions into non-integral powers.at n=5A000158
- Coefficient of q^(2n-1) in the series expansion of Ramanujan's mock theta function f(q).at n=13A000199
- a(n) = sigma(n), the sum of the divisors of n. Also called sigma_1(n).at n=44A000203
- a(n) = a(n-1) + a(n-2) - 2, a(0) = 4, a(1) = 3.at n=9A000211
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=67A000378
- Numbers that are the sum of three nonzero squares.at n=50A000408
- Numbers that are the sum of 4 nonzero squares.at n=62A000414
- Numbers that are the sum of 3 but no fewer nonzero squares.at n=32A000419
- Normalized total height of all nodes in all rooted trees with n labeled nodes.at n=3A000435
- The greedy sequence of integers which avoids 3-term geometric progressions.at n=56A000452
- 1 together with products of 2 or more distinct primes.at n=27A000469
- Number of steps to reach 1 in sequence A000546.at n=24A000547
- A Beatty sequence: [ n(e+1) ].at n=20A000572