2549
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
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2550
- 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
- 2548
- Möbius Function
- -1
- Radical
- 2549
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 373
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p == 3, 9, 11 (mod 20) such that 2p+1 is also prime.at n=36A000355
- Primes of the form k^2 - k - 1.at n=28A002327
- Prime self (or Colombian) numbers: primes not expressible as the sum of an integer and its digit sum.at n=38A006378
- Coordination sequence T1 for Zeolite Code AFG.at n=35A008012
- Coordination sequence T1 for Zeolite Code LIO.at n=35A008129
- Coordination sequence T2 for Zeolite Code RTH.at n=35A009894
- Numbers k such that the continued fraction for sqrt(k) has period 45.at n=4A020384
- Pisot sequence E(4,10).at n=7A020709
- Let q_k=p(p+2) be product of k-th pair of twin primes; sequence gives values of p such that (q_k)^2 > q_{k-i}q_{k+i} for all 1 <= i <= k-1.at n=23A021005
- Primes that remain prime through 2 iterations of the function f(x) = 2x + 9.at n=45A023245
- Primes that remain prime through 2 iterations of function f(x) = 8x + 7.at n=22A023263
- Primes that remain prime through 2 iterations of function f(x) = 9x + 2.at n=36A023265
- Primes that remain prime through 3 iterations of function f(x) = 8x + 7.at n=1A023294
- Primes that remain prime through 3 iterations of function f(x) = 9x + 2.at n=11A023296
- Primes that remain prime through 4 iterations of function f(x) = 9x + 2.at n=4A023324
- Convolution of A023532 and primes.at n=40A023606
- Number of positive integers that are not the sum of distinct n-th-order polygonal numbers.at n=25A025524
- a(n) = n + (n+1)^2.at n=49A028387
- Primes that are palindromic in base 7.at n=9A029975
- Cube root of A030683.at n=37A030684