126
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 312
- Proper Divisor Sum (Aliquot Sum)
- 186
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 36
- Möbius Function
- 0
- Radical
- 42
- Omega Function (Ω)
- 4
- 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
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 108
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- einshundertsechsundzwanzig· ordinal: einshundertsechsundzwanzigste
- English
- one hundred twenty-six· ordinal: one hundred twenty-sixth
- Spanish
- ciento veintiséis· ordinal: 126º
- French
- cent vingt-six· ordinal: cent vingt-sixième
- Italian
- centoventisei· ordinal: 126º
- Latin
- centum viginti sex· ordinal: 126.
- Portuguese
- cento e vinte e seis· ordinal: 126º
Appears in sequences
- 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=58A000028
- Number of necklaces with n beads of 2 colors, allowing turning over (these are also called bracelets).at n=11A000029
- Generalized tangent numbers d(n,1).at n=42A000061
- Smallest number of vertices in trivalent graph with girth (shortest cycle) = n.at n=9A000066
- a(n) = sigma(n), the sum of the divisors of n. Also called sigma_1(n).at n=67A000203
- Generalized class numbers c_(n,1).at n=8A000233
- Binomial coefficient binomial(n,4) = n*(n-1)*(n-2)*(n-3)/24.at n=9A000332
- Binomial coefficients C(n,5).at n=9A000389
- Numbers that are the sum of 3 but no fewer nonzero squares.at n=52A000419
- n written in base where place values are positive cubes.at n=49A000433
- A Beatty sequence: [ n(e+1) ].at n=33A000572
- Coefficient of x^5 in expansion of (1 + x + x^2)^n.at n=3A000574
- Expansion of Product_{n>=1} (1 - x^n)^7.at n=12A000730
- Numbers beginning with a vowel in English.at n=40A000852
- Numbers beginning with letter 'o' in English.at n=27A000865
- a(n) = 2^n - 2.at n=7A000918
- Numbers that are divisible by at least three different primes.at n=13A000977
- Partial sums of A001037, omitting A001037(1).at n=8A001036
- Dimensions (sorted, with duplicates removed) of real simple Lie algebras.at n=34A001066
- Related to S(n), the number of self-dual monotone Boolean functions of n variables (A001206): 2^n-th term is S(n).at n=18A001087