1381
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1382
- 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
- 1380
- Möbius Function
- -1
- Radical
- 1381
- 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
- 127
- 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
- 221
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of primes < prime(n)^2.at n=27A000879
- Primes p of the form 3k+1 such that sum_{x=1..p} cos(2*Pi*x^3/p) < -sqrt(p).at n=20A000923
- a(n) = ceiling(1000*log_10(n)).at n=23A004227
- Class 4- primes (for definition see A005109).at n=32A005112
- Primes p such that (p+1)/2 is prime.at n=27A005383
- Centered pentagonal numbers: (5n^2+5n+2)/2; crystal ball sequence for 3.3.3.4.4. planar net.at n=23A005891
- Erroneous version of A223911: Tiered orders on n nodes.at n=4A006860
- Primes with both 10 and -10 as primitive root.at n=42A007349
- Reflectable emirps.at n=9A007628
- Primes of the form 2*k^2 + 29.at n=26A007641
- Coordination sequence T2 for Zeolite Code EUO.at n=23A008097
- Coordination sequence T1 for Zeolite Code GME and AFX.at n=28A008110
- Coordination sequence T1 for Milarite.at n=23A008256
- a(n) = floor(n*(n - 1)*(n - 2)/31).at n=36A011913
- Multiplicity of trivial character in V_n, where V = Sum V_n is the graded module for the Monster simple group.at n=28A014810
- Expansion of x/(1 - 5*x - 9*x^2).at n=5A015545
- Ceiling of Gamma(n+4/7)/Gamma(4/7).at n=7A020121
- Numbers k such that the continued fraction for sqrt(k) has period 67.at n=0A020406
- Smallest nonempty set S containing prime divisors of 6k+7 for each k in S.at n=40A020604
- Place where n-th 1 occurs in A023133.at n=29A022795