13218
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 26448
- Proper Divisor Sum (Aliquot Sum)
- 13230
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 4404
- Möbius Function
- -1
- Radical
- 13218
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 138
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Number of partitions into non-integral powers.at n=42A000327
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite RON = Roggianite Ca16[Be8Al16Si32O104(OH)16].19H2O starting with a T3 atom.at n=13A019215
- Square root of A030681.at n=39A030682
- Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,21.at n=19A064247
- Admirable numbers in the middle of twin primes.at n=34A135502
- Numbers that are divisible by exactly 3 primes (counted with multiplicity) and sandwiched between primes.at n=33A171179
- Sequence of the "Natural Jewels": a natural jewel is a number that is totally enclosed by prime numbers in a version of Ulam Spiral.at n=10A172294
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209140; see the Formula section.at n=49A209139
- a(n) = 420*2^n - 222.at n=5A304614
- Numbers on the square spiral board that are enclosed by four primes.at n=11A341542
- Numbers of the form prime(i-1)+prime(i+1) that are the average of a twin prime pair.at n=46A342993
- Numbers whose second arithmetic derivative (A068346) is a primorial number (A002110) > 1.at n=18A368702
- Total number of modes in all partitions of n.at n=33A372542