13457
domain: N
Properties
Digital Properties
- Digit Count
- 5
- 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
- 13458
- 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
- 13456
- Möbius Function
- -1
- Radical
- 13457
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 138
- 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
- 1595
- 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=20A002496
- a(n) = T(2n-1,n-1), T given by A026703.at n=6A026707
- T(n,[ n/2 ]), T given by A026703.at n=13A026709
- Lists of 4 primes in arithmetic progression; common difference 6.at n=33A033449
- Second member of a sexy prime quadruple: value of p+6 such that p, p+6, p+12 and p+18 are all prime.at n=27A046122
- Totient(n) and cototient(n) are squares.at n=39A054754
- Odd powers of primes of the form q = x^2 + 1 (A002496).at n=29A054755
- Second term of balanced prime quartets: p(m)-p(m-1) = p(m+1)-p(m) = p(m+2)-p(m+1).at n=8A054801
- Numbers whose divisors have the form m^k + 1, k>1.at n=22A054964
- Number of 1's in binary expansion of parts in all partitions of n.at n=23A066624
- Primes p such that the period of the decimal expansion of 1/p is a square.at n=20A072858
- Shifts one place left under 8th-order binomial transform.at n=5A075507
- Primes p such that (p-1) and the period length of 1/p are both squares.at n=10A076516
- Primes of the form m*rad(m)+1, where rad = A007947 (squarefree kernel).at n=34A078324
- a(n) = index of first appearance of n in A096862.at n=16A097008
- a(n) = 16*n^2 + 1.at n=28A108211
- Primes of the form 4*k^2 + 1.at n=19A121326
- Primes p of the form 4*n^2 + 1 such that 4*p^2+1 is also prime.at n=6A121834
- Primes in the sequence a(n)=n^2+3/2-1/2*(-1)^n.at n=32A125557
- Primes p for which the period length of 1/p is a perfect power, A001597.at n=27A128948