12621
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19264
- Proper Divisor Sum (Aliquot Sum)
- 6643
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7200
- Möbius Function
- -1
- Radical
- 12621
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 94
- 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
- no
- Odd
- yes
Appears in sequences
- Octal palindromes which are also primes.at n=21A006341
- Pseudoprimes to base 13.at n=32A020141
- Palindromic lucky numbers.at n=34A031161
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 74.at n=36A031572
- Lucky numbers that are both palindromic and nonprime.at n=28A031880
- Denominators of continued fraction convergents to sqrt(763).at n=11A042471
- Palindromic and divisible by 7.at n=37A045642
- Concatenation of factorials in increasing order up to the n-th and then in decreasing order.at n=2A066625
- Numbers n of the form k + reverse(k) for exactly three k.at n=28A071914
- Palindromic odd composite numbers that are the products of an odd number of distinct primes.at n=27A075808
- Palindromic odd numbers with exactly 3 prime factors (counted with multiplicity).at n=40A075814
- a(n) = sigma_3(n^3)/sigma(n^3).at n=4A077454
- Smallest multiple of n which begins with R(n) and ends in n where R(n) (A004086) is the digit reversal of n. Suitable number of zeros are assumed to the left of the MSD if required.at n=20A077741
- Smallest palindrome beginning with n and digit sum n, or 0 if no such number exists.at n=11A082217
- Palindromic time display in hours, minutes, seconds on a six spaced 24-hour digital clock, using hours 1-24.at n=26A082567
- Smallest palindrome beginning with n and a digit sum of n at some stage.at n=11A082935
- a(n) = concatenate(n, A010888(2*n), reverse(n)), where A010888 = digital root.at n=11A082944
- Smallest palindromic multiple of n in which n is a substring (anywhere), or 0 if n = 10k or no such number exists.at n=20A084044
- Number of compositions (ordered partitions) of n into powers of 4.at n=31A087221
- G.f. satisfies A(x) = f(x) + x*A(x)*f(x)^3, where f(x) = Sum_{k>=0} x^((4^k-1)/3).at n=10A087223