2381
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2382
- 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
- 2380
- Möbius Function
- -1
- Radical
- 2381
- 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
- 76
- 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
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 353
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/5.at n=6A001135
- Centered square numbers: a(n) = 2*n*(n+1)+1. Sums of two consecutive squares. Also, consider all Pythagorean triples (X, Y, Z=Y+1) ordered by increasing Z; then sequence gives Z values.at n=34A001844
- Numbers that are the sum of 8 positive 6th powers.at n=27A003364
- Number of trees with stability index n.at n=9A003429
- Primitive prime factors of the sequence k^2 + 1 (A002522) in the order that they are found.at n=49A005529
- From relations between Siegel theta series.at n=27A006476
- Coordination sequence T3 for Zeolite Code BRE.at n=32A008060
- Coordination sequence T1 for Zeolite Code GOO.at n=33A008111
- Coordination sequence T3 for Zeolite Code HEU.at n=32A008118
- Coordination sequence T5 for Zeolite Code MTW.at n=32A008200
- "Pascal sweep" for k=8: draw a horizontal line through the 1 at C(k,0) in Pascal's triangle; rotate this line and record the sum of the numbers on it (excluding the initial 1).at n=48A009522
- Coordination sequence T1 for Zeolite Code OSI.at n=32A016430
- Conjectured formula for irreducible 5-fold Euler sums of weight 2n+13.at n=26A019450
- Numbers k such that the continued fraction for sqrt(k) has period 55.at n=0A020394
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Fibonacci numbers), t = A001950 (upper Wythoff sequence).at n=16A024465
- Sequence satisfies T(a)=a, where T is defined below.at n=40A027592
- Primes of the form j^2 + (j+1)^2.at n=16A027862
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 22 ones.at n=22A031790
- a(n) = prime(8*n - 7).at n=44A031915
- a(n) = prime(9*n-7).at n=39A031916