7420
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 18144
- Proper Divisor Sum (Aliquot Sum)
- 10724
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2496
- Möbius Function
- 0
- Radical
- 3710
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 119
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Rencontres numbers: number of permutations of [n] with exactly two fixed points.at n=8A000387
- Triangle T(n,k) of rencontres numbers (number of permutations of n elements with k fixed points).at n=38A008290
- Triangle of rencontres numbers.at n=23A008291
- Four times second pentagonal numbers: a(n) = 2*n*(3*n+1).at n=35A033580
- Numbers whose base-4 representation contains exactly two 0's and four 3's.at n=18A045075
- Iterated procedure 'composite k added to sum of its prime factors reaches a prime' yields 7 skipped primes.at n=40A050774
- Molien series for group H_{1,3}^{8} of order 2304.at n=29A051531
- McKay-Thompson series of class 38a for Monster.at n=41A058658
- Total number of abstract order types of configurations of n points in dimensions 2 through n-1.at n=4A063857
- a(n) = (prime(n)-1)*(prime(n)+1)/6.at n=44A084922
- Numbers n such that A001414(n) = sum of squared digits of n.at n=14A094908
- Triangle read by rows: T(n,k) = number of partial derangements, that is, the number of permutations of n distinct, ordered items in which exactly k of the items are in their natural ordered positions, for n >= 0, k = n, n-1, ..., 1, 0.at n=42A098825
- Triangle T, read by rows, that satisfies the recurrence: T(n,k) = [T^5](n-1,k-1) + [T^5](n-1,k) for n>k>=0, with T(n,n)=1 for n>=0, where T^5 is the matrix 5th power of T.at n=11A113106
- Sum of the odd parts in all partitions of n into distinct parts.at n=33A116682
- Sum of all n-digit Apery numbers.at n=3A131972
- a(n) = floor(n^sqrt(2*Pi)).at n=34A134887
- Square array, read by antidiagonals, where row n+1 is generated from row n by first removing terms at positions [(m+3)^2/4 - 2] for m>=0 and then taking partial sums, starting with all 1's in row 0.at n=39A135878
- a(n) = least m such that sum of m reciprocal primes starting with n-th prime is >1.at n=16A137368
- Binomial transform of [1, 3, 3, 1, 1, -1, 1, -1, 1, ...].at n=28A140226
- T(n,k) is the number of partial bijections (or subpermutations) of an n-element set of height k (height(alpha) = |Im(alpha)|) and with exactly 2 fixed points.at n=27A144091