287
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
- 336
- Proper Divisor Sum (Aliquot Sum)
- 49
- 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
- 240
- Möbius Function
- 1
- Radical
- 287
- 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
- yes
- 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
- no
- Odd
- yes
Names
- German
- zweihundertsiebenundachtzig· ordinal: zweihundertsiebenundachtzigste
- English
- two hundred eighty-seven· ordinal: two hundred eighty-seventh
- Spanish
- doscientos ochenta y siete· ordinal: 287º
- French
- deux cent quatre-vingt-sept· ordinal: deux cent quatre-vingt-septième
- Italian
- duecentoottantasette· ordinal: 287º
- Latin
- ducenti octoginta septem· ordinal: 287.
- Portuguese
- duzentos e oitenta e sete· ordinal: 287º
Appears in sequences
- Let A(n) = #{(i,j): i^2 + j^2 <= n}, V(n) = Pi*n, P(n) = A(n) - V(n); sequence gives values of n where |P(n)| sets a new record.at n=13A000099
- Pentagonal numbers: a(n) = n*(3*n-1)/2.at n=14A000326
- Generalized pentagonal numbers: m*(3*m - 1)/2, m = 0, +-1, +-2, +-3, ....at n=27A001318
- a(n) = a(n-1) + a(n-2) + 1, with a(0) = a(1) = 1.at n=11A001595
- a(n) = -a(n-1) - 2*a(n-2).at n=21A001607
- Numbers k such that 13*2^k - 1 is prime.at n=3A001773
- Related to graded partially ordered sets.at n=3A001828
- Expansion of g.f. x/((1 - x)^2*(1 - x^3)).at n=40A001840
- A Beatty sequence: floor(n * (sqrt(5) + 3)).at n=54A001962
- Inverse of reduced totient function.at n=46A002396
- Numbers k such that (k^2 + 1)/10 is prime.at n=29A002733
- Numbers m such that 6m-1, 6m+1 are twin primes.at n=53A002822
- Smallest number requiring n chisel strokes for its representation in Roman numerals.at n=15A002964
- Problimes (third definition).at n=50A003068
- Sorting numbers: maximal number of comparisons for sorting n elements by list merging.at n=57A003071
- a(n) = A000201(A003234(n)) + n.at n=41A003248
- Ludic numbers: apply the same sieve as Eratosthenes, but cross off every k-th remaining number.at n=52A003309
- 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=48A003311
- Number of atoms in a decahedron with n shells.at n=7A004068
- Pentagonal numbers written backwards.at n=23A004163