7447
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8136
- Proper Divisor Sum (Aliquot Sum)
- 689
- 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
- 6760
- Möbius Function
- 1
- Radical
- 7447
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 132
- Smith Number
- yes
- 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
- a(1) = 0, a(2) = -2; for n > 2, a(n) + a(n-2) - a(n-3) - a(n-5) - ... - a(n-p) = (-1)^(n+1)*n if n is prime, otherwise = 0, where p = largest prime < n.at n=54A002120
- Numbers k such that x^k + x + 1 is irreducible over GF(2).at n=27A002475
- Numbers that are palindromic in bases 2 and 10.at n=11A007632
- a(n) = n*(n-1) + (n-2)*(n-3) + ... + 1*0 + 1 for n odd; otherwise, a(n) = n*(n-1) + (n-2)*(n-3) + ... + 2*1.at n=34A014112
- Palindromic lucky numbers.at n=24A031161
- Lucky numbers that are both palindromic and nonprime.at n=19A031880
- Digit sum of 'odd' number equals digit sum of 'sum' and 'juxtaposition' of its prime factors (counted with multiplicity).at n=36A036927
- Numerators of continued fraction convergents to sqrt(414).at n=5A041786
- Base-10 palindromes that start with 7.at n=16A043042
- Numbers whose base-5 representation contains exactly three 2's and two 4's.at n=30A045291
- Palindromes with exactly 2 prime factors (counted with multiplicity).at n=45A046328
- Palindromes with exactly 2 distinct prime factors.at n=42A046392
- Array read by antidiagonals: T(k,d) = number of different hyperplanes in d-space with integer coefficients in set {-k,...,-1,0,1,...,k}.at n=19A061559
- Numbers that are palindromic in base 2 as well as in base 10 (initial zeros may be prepended).at n=37A069024
- Palindromic numbers which are products of an even number of distinct primes.at n=51A075799
- Palindromic odd squarefree numbers with an even number of distinct prime factors.at n=36A075810
- Palindromic odd numbers with exactly 2 prime factors (counted with multiplicity).at n=34A075812
- Numbers n such that RevBinary(RevDecimal(n))=RevDecimal(RevBinary(n)), where RevDecimal(n) is the decimal reversal of n (A004086) and RevBinary(n) is the binary reversal of n (A030101).at n=39A081433
- Numbers such that RevBinary() = RevDecimal(), where RevDecimal(n) is the decimal reversal of n (A004086) and RevBinary(n) is the binary reversal of n (A030101).at n=17A081434
- Palindromes arising in A082270.at n=28A082271