13213
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13468
- Proper Divisor Sum (Aliquot Sum)
- 255
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12960
- Möbius Function
- 1
- Radical
- 13213
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 76
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- cos(tanh(x)+log(x+1))=1-4/2!*x^2+6/3!*x^3+13/4!*x^4-20/5!*x^5...at n=8A013122
- Odd heptagonal numbers (A000566).at n=36A014637
- Pseudoprimes to base 65.at n=43A020193
- Pseudoprimes to base 72.at n=34A020200
- Strong pseudoprimes to base 19.at n=14A020245
- Strong pseudoprimes to base 61.at n=9A020287
- Strong pseudoprimes to base 92.at n=23A020318
- a(n) = (2*n + 1)*(5*n + 1).at n=36A033571
- Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,3,2.at n=4A037617
- Triangle read by rows: number of nonisomorphic semigroups of order n with k idempotents.at n=27A058108
- Number of isomorphism classes of idempotent semigroups of order n.at n=7A058112
- Nonprimes k such that k divides 3^(k-1) - 2^(k-1).at n=27A073631
- Largest proper divisor of the n-th Carmichael number (A002997).at n=31A081703
- Numbers k (with no zero digits) with property that k raised to the product of its digits plus the sum of its digits is prime.at n=13A098797
- Number of orbits of the 4-step recursion mod n.at n=44A106286
- Apocalypse primes: 10^665+a(n) has 666 decimal digits and is prime.at n=7A115983
- Heptagonal numbers for which the product of the digits is also a heptagonal number.at n=5A117661
- Heptagonal numbers for which the digital root is also a heptagonal number.at n=33A117663
- Numbers k such that binomial(3k, k) + 1 is prime.at n=22A125221
- Expansion of 1/(x^k*(1-x-3*x^(k+1))) for k=8.at n=30A143459