1213
domain: N
Properties
Digital Properties
- Digit Count
- 4
- 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
- 1214
- 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
- 1212
- Möbius Function
- -1
- Radical
- 1213
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 44
- Smith Number
- no
- Vampire 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
- 198
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p of the form 3k+1 such that Sum_{x=1..p} cos(2*Pi*x^3/p) > sqrt(p).at n=50A000921
- A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n.at n=39A001149
- a(n) = n concatenated with n + 1.at n=11A001704
- Number of solutions to a linear inequality.at n=31A002797
- Number of graphical partitions (degree-vectors for simple graphs with n vertices, or possible ordered row-sum vectors for a symmetric 0-1 matrix with diagonal values 0).at n=8A004251
- Primes written in base 4.at n=26A004678
- Class 4+ primes (for definition see A005105).at n=19A005108
- Primes p such that (p+1)/2 is prime.at n=24A005383
- Positions of remoteness 3 in Beans-Don't-Talk.at n=22A005695
- 11*n^2 + 11*n + 3.at n=10A006222
- Where the prime race among 5k+1, ..., 5k+4 changes leader.at n=11A007353
- Inverse binomial transform of primes.at n=12A007442
- Primes of the form 8k + 5.at n=51A007521
- Numbers that contain only 1's, 2's and 3's.at n=50A007932
- Coordination sequence T1 for Zeolite Code MFI.at n=22A008161
- Coordination sequence T2 for Scapolite.at n=22A008263
- Coordination sequence T1 for Zeolite Code -PAR.at n=25A009855
- a(n) = floor( n*(n-1)*(n-2)*(n-3)/27 ).at n=15A011937
- a(n) is prime and sum of all primes <= a(n) is prime.at n=23A013917
- Numbers k such that sigma(k) + 4 = sigma(k+4).at n=44A015913