3
domain: N
Properties
Digital Properties
- Digit Count
- 1
- Digit Sum
- 3
- Digital Root
- 3
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 0
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 4
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 2
- Möbius Function
- -1
- Radical
- 3
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- yes
- Triangular Number
- yes
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- yes
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- yes
- Collatz Steps
- 7
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- yes
- Sophie Germain Prime
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 2
- Perfect Power
- no
- Smooth Number
- yes
- Carmichael Number
- no
Names
- German
- drei· ordinal: dritte
- English
- three· ordinal: third
- Spanish
- tres· ordinal: tercero
- French
- trois· ordinal: troisième
- Italian
- tre· ordinal: terzo
- Latin
- tres· ordinal: tertius
- Portuguese
- três· ordinal: terceiro
Appears in sequences
- Number of groups of order n.at n=75A000001
- Number of classes of primitive positive definite binary quadratic forms of discriminant D = -4n; or equivalently the class number of the quadratic order of discriminant D = -4n.at n=10A000003
- Number of classes of primitive positive definite binary quadratic forms of discriminant D = -4n; or equivalently the class number of the quadratic order of discriminant D = -4n.at n=18A000003
- Number of classes of primitive positive definite binary quadratic forms of discriminant D = -4n; or equivalently the class number of the quadratic order of discriminant D = -4n.at n=22A000003
- Number of classes of primitive positive definite binary quadratic forms of discriminant D = -4n; or equivalently the class number of the quadratic order of discriminant D = -4n.at n=26A000003
- Number of classes of primitive positive definite binary quadratic forms of discriminant D = -4n; or equivalently the class number of the quadratic order of discriminant D = -4n.at n=30A000003
- Number of classes of primitive positive definite binary quadratic forms of discriminant D = -4n; or equivalently the class number of the quadratic order of discriminant D = -4n.at n=42A000003
- Number of classes of primitive positive definite binary quadratic forms of discriminant D = -4n; or equivalently the class number of the quadratic order of discriminant D = -4n.at n=66A000003
- d(n) (also called tau(n) or sigma_0(n)), the number of divisors of n.at n=3A000005
- d(n) (also called tau(n) or sigma_0(n)), the number of divisors of n.at n=8A000005
- d(n) (also called tau(n) or sigma_0(n)), the number of divisors of n.at n=24A000005
- d(n) (also called tau(n) or sigma_0(n)), the number of divisors of n.at n=48A000005
- Integer part of square root of n-th prime.at n=4A000006
- Integer part of square root of n-th prime.at n=5A000006
- Number of ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=4A000008
- Expansion of Product_{m >= 1} (1 + x^m); number of partitions of n into distinct parts; number of partitions of n into odd parts.at n=5A000009
- Smallest prime power >= n.at n=2A000015
- Number of primitive permutation groups of degree n.at n=51A000019
- Coefficients of the 3rd-order mock theta function f(q).at n=3A000025
- Coefficients of the 3rd-order mock theta function f(q).at n=5A000025