13381
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 13382
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13380
- Möbius Function
- -1
- Radical
- 13381
- 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
- 138
- 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
- 1587
- 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=33A001135
- Numbers that are the sum of 6 nonzero 8th powers.at n=14A003384
- a(n) = a(n-2) + a(n-3), with a(0) = 0, a(1) = 1, a(2) = 4.at n=33A007309
- Value of D for incrementally largest values of minimal x satisfying Pell equation x^2-Dy^2=1.at n=35A033316
- Primes which are not the sum of consecutive composite numbers.at n=37A037174
- a(1) = 2, a(2) = 3 and a(n) = the smallest prime which is a linear combination of all previous terms with all coefficients >= 1.at n=13A072537
- a(1) = 1, a(n) = smallest number > a(n-1) such that concatenation a(k) a(n) is prime for all k = 1 to n-1. Stop if no such number exists.at n=6A075611
- a(1)=2; for n>1, a(n+1) = least prime > a(n) and congruent to a prime modulo prime successor of a(n).at n=11A080898
- a(1) = 1, then the smallest number such that the concatenation a(r), a(s) is prime for all s > r.at n=7A088647
- Smallest prime p == 5 mod 8 (A007521) and p > prime(n+2) such that p is a quadratic residue mod the first n odd primes 3, 5, 7, 11, ..., prime(n+1), and p is a quadratic non-residue mod prime(n+2).at n=8A096639
- Expansion of (1-4x)/(1-x^2+x^3).at n=32A117379
- Primes which are the sum of a twin prime pair + 1.at n=40A118071
- Smallest prime p such that the maximum run length of consecutive quadratic nonresidues modulo p is n.at n=28A129201
- Prime numbers p such that p +- ((p-1)/2) are primes.at n=30A137702
- Prime numbers, isolated from neighboring primes by more than 12.at n=31A137873
- Primes of the form x^2 + 1365*y^2.at n=33A139667
- 1 together with terms of A037174.at n=38A140464
- Primes congruent to 15 mod 41.at n=32A142212
- Primes congruent to 8 mod 43.at n=39A142257
- Primes congruent to 33 mod 47.at n=36A142384