866
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 1302
- Proper Divisor Sum (Aliquot Sum)
- 436
- 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
- 432
- Möbius Function
- 1
- Radical
- 866
- 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
- 28
- 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
- achthundertsechsundsechzig· ordinal: achthundertsechsundsechzigste
- English
- eight hundred sixty-six· ordinal: eight hundred sixty-sixth
- Spanish
- ochocientos sesenta y seis· ordinal: 866º
- French
- huit cent soixante-six· ordinal: huit cent soixante-sixième
- Italian
- ottocentosessantasei· ordinal: 866º
- Latin
- octingenti sexaginta sex· ordinal: 866.
- Portuguese
- oitocentos e sessenta e seis· ordinal: 866º
Appears in sequences
- Construct a triangle as in A036262. Sequence is one less than the position of the first number larger than 2 in the n-th row (n-th difference).at n=33A000232
- a(n) = a(n-1)^2 + a(n-2)^2 for n >= 2 with a(0) = 0 and a(1) = 1.at n=6A000283
- Smallest nonnegative number that is the sum of 3 squares in exactly n ways.at n=11A000437
- Smallest number that is the sum of 3 squares in at least n ways.at n=11A000451
- Numbers in which every digit contains at least one loop (version 1).at n=37A001743
- Numbers that are the sum of 12 positive 6th powers.at n=15A003368
- a(n) = 6*n^2 + 2 for n > 0, a(0)=1.at n=12A005897
- Numbers k such that k^8 + 1 is prime.at n=32A006314
- Number of one-sided triangular polyominoes (n-iamonds) with n cells; turning over not allowed, holes are allowed.at n=9A006534
- E-trees with exactly 2 colors.at n=6A007143
- Oscillates under partition transform.at n=29A007210
- Oscillates under partition transform.at n=27A007211
- Number of elements (a b, c d) in GL(2,Z) with |det| = 1, trace <= n and 0 <= a <= {b, c} <= d.at n=44A007295
- Coordination sequence T3 for Zeolite Code EMT.at n=24A008088
- Coordination sequence T1 for Zeolite Code MEL.at n=19A008150
- Coordination sequence T1 for Zeolite Code MON.at n=18A008181
- Smallest number strictly greater than previous one which is the sum of squares of two previous distinct terms (a(1)=1, a(2)=2).at n=10A008318
- Molien series for A_5.at n=30A008628
- Coordination sequence T3 for Zeolite Code VET.at n=18A009904
- a(0) = 1, a(n) = 24*n^2 + 2 for n>0.at n=6A010014