3151
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3312
- Proper Divisor Sum (Aliquot Sum)
- 161
- 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
- 2992
- Möbius Function
- 1
- Radical
- 3151
- 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
- 61
- Smith Number
- no
- Vampire 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
Appears in sequences
- Pentagonal numbers: a(n) = n*(3*n-1)/2.at n=46A000326
- Number of forests of least height with n nodes.at n=7A001862
- Expansion of (1+x)(1+x^2)/(1-x-x^3).at n=20A003410
- Centered pentagonal numbers: (5n^2+5n+2)/2; crystal ball sequence for 3.3.3.4.4. planar net.at n=35A005891
- Weighted count of partitions with distinct parts.at n=27A005895
- Molien series for A_5.at n=43A008628
- Coordination sequence for MgNi2, Position Mg2.at n=14A009935
- Coordination sequence for MgNi2, Position Mg1.at n=14A009936
- Odd pentagonal numbers.at n=23A014632
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite EPI = Epistilbite Ca3[Al6Si18O48].16H2O starting with a T2 atom.at n=11A019118
- Numbers k such that the continued fraction for sqrt(k) has period 44.at n=25A020383
- a(n) = least m such that if r and s in {1/1, 1/4, 1/7, ..., 1/(3n-2)} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=25A024836
- Coordination sequence T5 for Zeolite Code MWW.at n=37A024990
- a(n) = dot_product(1,2,...,n)*(7,8,...,n,1,2,3,4,5,6).at n=16A026049
- Number of partitions of n in which the least part is 6.at n=69A026799
- Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 24 (most significant digit on right and removing all least significant zeros before concatenation).at n=6A029541
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 55.at n=11A031553
- "AGK" (ordered, elements, unlabeled) transform of 1,3,5,7...at n=8A032026
- Numbers whose set of base-7 digits is {1,2}.at n=40A032928
- Numbers whose set of base-14 digits is {1,2}.at n=18A032934