331
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 332
- 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
- 330
- Möbius Function
- -1
- Radical
- 331
- 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
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 24
- Smith Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 67
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- dreihunderteinunddreißig· ordinal: dreihunderteinunddreißigste
- English
- three hundred thirty-one· ordinal: three hundred thirty-first
- Spanish
- trescientos treinta y uno· ordinal: 331º
- French
- trois cent trente et un· ordinal: trois cent trente et unième
- Italian
- trecentotrentuno· ordinal: 331º
- Latin
- trecenti triginta unus· ordinal: 331.
- Portuguese
- trezentos e trinta e um· ordinal: 331º
Appears in sequences
- Euler transform of A000292.at n=5A000335
- Number of twin prime pairs < square of n-th prime.at n=33A000885
- Primes p of the form 3k+1 such that sum_{x=1..p} cos(2*Pi*x^3/p) < -sqrt(p).at n=5A000923
- Primes with 3 as smallest primitive root.at n=15A001123
- Table T(n,k) in which n-th row lists prime factors of 2^n + 1 (n >= 0), with repetition.at n=32A001269
- a(n) is the number of partitions of n into at most 3 parts; also partitions of n+3 in which the greatest part is 3; also number of unlabeled multigraphs with 3 nodes and n edges.at n=60A001399
- Number of partitions of n into at most 6 parts.at n=21A001402
- a(1)=2, a(2)=3; for n >= 3, a(n) is smallest number that is uniquely of the form a(j) + a(k) with 1 <= j < k < n.at n=56A001857
- Prime determinants of forms with class number 2.at n=32A002052
- Primes of the form 4*k + 3.at n=34A002145
- Numbers k for which the rank of the elliptic curve y^2 = x^3 + k is 2.at n=48A002155
- Smallest primitive factor of 2^(2n+1) + 1.at n=7A002185
- Smallest prime p such that first n primes (p_1=2, ..., p_n) are 11th power residues mod p.at n=0A002228
- Denominators of convergents to cube root of 5.at n=6A002357
- Cuban primes: primes which are the difference of two consecutive cubes.at n=6A002407
- Squares written in base 7.at n=12A002440
- Primes of the form 6m + 1.at n=30A002476
- Largest prime factor of 2^n + 1.at n=15A002587
- Largest primitive factor of 2^(2n+1) + 1.at n=7A002589
- Numbers k such that (k^2 + k + 1)/21 is prime.at n=18A002644