2909
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2910
- 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
- 2908
- Möbius Function
- -1
- Radical
- 2909
- 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
- 48
- 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
- 421
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers of Twopins positions.at n=19A005688
- Coordination sequence T3 for Zeolite Code ATS.at n=39A008040
- If a, b in sequence, so is ab+7.at n=27A009312
- Numbers k such that the continued fraction for sqrt(k) has period 61.at n=1A020400
- Primes that remain prime through 2 iterations of function f(x) = 7x + 6.at n=37A023259
- Primes that remain prime through 2 iterations of function f(x) = 8x + 7.at n=25A023263
- Convolution of natural numbers with composite numbers.at n=19A023539
- a(n) = sum of the numbers between the two n's in A026346.at n=35A026349
- Primes of the form k^2 - 7.at n=7A028883
- Size of lexicographic code of length n, Hamming distance 8 and weight 8.at n=32A030069
- Primes with property that when squared all even digits occur together and all odd digits occur together.at n=32A030480
- Concatenation of n consecutive primes starting with the prime a(n) is a prime.at n=53A030996
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 28 ones.at n=14A031796
- a(n) = prime(10*n-9).at n=42A031920
- Lower prime of a difference of 8 between consecutive primes.at n=39A031926
- Primes of form x^2+29*y^2.at n=30A033219
- Primes of form x^2+41*y^2.at n=20A033228
- Primes of form x^2+77*y^2.at n=17A033249
- Number of partitions of n such that cn(0,5) = cn(2,5) <= cn(1,5) <= cn(3,5) = cn(4,5).at n=59A036848
- Denominators of continued fraction convergents to sqrt(610).at n=8A042171