16901
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 16902
- 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
- 16900
- Möbius Function
- -1
- Radical
- 16901
- 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
- 58
- 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
- 1949
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes of the form k^2 + 1.at n=24A002496
- Primes that remain prime through 3 iterations of function f(x) = 2x + 9.at n=33A023276
- Primes that remain prime through 4 iterations of function f(x) = 2x + 9.at n=14A023306
- a(n) = A006496(n)/2.at n=13A045873
- Odd powers of primes of the form q = x^2 + 1 (A002496).at n=33A054755
- Numbers whose divisors have the form m^k + 1, k>1.at n=26A054964
- Primes p whose period of reciprocal equals (p-1)/5.at n=36A056210
- Numbers k such that sigma(k+2) - sigma(k) = prime(k+1) - prime(k).at n=38A067062
- Primes of the form m*rad(m)+1, where rad = A007947 (squarefree kernel).at n=39A078324
- a(n) = 2^(n-1)*u(n) where u(1)=1 and u(n) = frac(3/2*u(n-1)) + 1.at n=14A079450
- Twin-prime-indexed primes (TWIPS): members of a pair of twin primes whose prime index is also a member of a pair of twin primes.at n=36A087373
- Primes p such that all prime factors of p-1 have exponent 2.at n=10A089195
- Smallest prime p such that tau(p-1) + tau(p+1) is n, or 0 if no such number exists.at n=42A090482
- "Secondary twin primes": a(n) = A006450(A096477(n)).at n=39A096479
- a(n) = n^3 - n^2 + 1.at n=26A100104
- Expansion of (1-4x+12x^2-16x^3+8x^4)/(1-x)^5.at n=26A119327
- Primes of the form 4*k^2 + 1.at n=23A121326
- Primes in the sequence a(n)=n^2+3/2-1/2*(-1)^n.at n=38A125557
- Primes associated with A127435.at n=10A127436
- Lesser of twin primes isolated from neighboring primes by +- 10 (or more).at n=32A138063