278
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 420
- Proper Divisor Sum (Aliquot Sum)
- 142
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 138
- Möbius Function
- 1
- Radical
- 278
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- 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
- 42
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
Classification
- Even
- yes
- Odd
- no
Names
- German
- zweihundertachtundsiebzig· ordinal: zweihundertachtundsiebzigste
- English
- two hundred seventy-eight· ordinal: two hundred seventy-eighth
- Spanish
- doscientos setenta y ocho· ordinal: 278º
- French
- deux cent soixante-dix-huit· ordinal: deux cent soixante-dix-huitième
- Italian
- duecentosettantotto· ordinal: 278º
- Latin
- ducenti septuaginta octo· ordinal: 278.
- Portuguese
- duzentos e setenta e oito· ordinal: 278º
Appears in sequences
- Numbers k such that k^4 + 1 is prime.at n=41A000068
- Number of nonnegative solutions to x^2 + y^2 + z^2 <= n.at n=53A000606
- Dimension of the n-th graded piece of the mod-2 Steenrod algebra A_2.at n=63A000929
- n! never ends in this many 0's.at n=53A000966
- Numbers that are the sum of 4 cubes in more than 1 way.at n=11A001245
- A Fielder sequence: a(n) = a(n-1) + a(n-2) + a(n-4).at n=9A001641
- 2 together with primes multiplied by 2.at n=34A001747
- a(1)=2, a(2)=3; for n >= 3, a(n) is smallest number that is uniquely of the form a(j) + a(k) with 1 <= j < k < n.at n=52A001857
- v-pile positions of the 4-Wythoff game with i=1.at n=53A001964
- Sum of totient function: a(n) = Sum_{k=1..n} phi(k), cf. A000010.at n=30A002088
- Generalized sum of divisors function.at n=16A002132
- a(n) is the number of partitions of 2n that can be obtained by adding together two (not necessarily distinct) partitions of n.at n=8A002219
- a(n) = Sum_{d|n, d <= 4} d^2 + 4*Sum_{d|n, d>4} d.at n=29A002791
- Numbers m such that 6m-1, 6m+1 are twin primes.at n=51A002822
- a(n) (n>6) is least integer > a(n-1) with precisely three representations a(n) = a(i) + a(j), 1 <= i < j < n, a(n) = n for n=1..6.at n=55A003045
- Positions of letter c in the tribonacci word abacabaabacababac... generated by a->ab, b->ac, c->a (cf. A092782).at n=44A003146
- a(n) = A000201(A003234(n)) + n.at n=40A003248
- Generated by a sieve.at n=59A003310
- Write down the numbers from 3 to infinity. Take next number, M say, that has not been crossed off. Counting through the numbers that have not yet been crossed off after that M, cross off the first, (M+1)st, (2M+1)st, (3M+1)st, etc. Repeat. The numbers that are left form the sequence.at n=46A003311
- Numbers that are the sum of 8 positive 4th powers.at n=26A003342