4721
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 4722
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 4720
- Möbius Function
- -1
- Radical
- 4721
- 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
- 121
- 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
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 636
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of partitions of n if there are two kinds of 1's and two kinds of 2's.at n=19A000097
- Primes with 6 as smallest primitive root.at n=35A001125
- Quartan primes: primes of the form x^4 + y^4, x > 0, y > 0.at n=12A002645
- Numbers that are the sum of 2 positive 4th powers.at n=31A003336
- G.f.: (1 + x^4 + x^7 + 2*x^8 + x^9 + x^12 + x^16)/Product_{i=1..8} (1 - x^i).at n=28A003405
- Numbers that are the sum of at most 2 nonzero 4th powers.at n=40A004831
- Primes p == 1 (mod 8), p = a^2 +64*b^2 such that y^2 = x^3 + p*x has rank 0.at n=22A007765
- Number of triples of different integers from [ 2,n ] with no common factors between pairs.at n=46A015620
- Numbers k such that the continued fraction for sqrt(k) has period 41.at n=11A020380
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A000201 (lower Wythoff sequence).at n=26A024685
- a(n) = least m such that if r and s in {1/1, 1/4, 1/7,..., 1/(3n-2)} satisfy r < s, then r < k/m < s for some integer k.at n=45A024822
- Sum{T(n-k,k)}, 0<=k<=[ n/2 ], T given by A026907.at n=10A026918
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 5.at n=26A031418
- Upper prime of a difference of 18 between consecutive primes.at n=16A031937
- Exactly 5 digits from {1,2,3,4,5,6,7,8,9} can precede a(n) to form a lucky number.at n=23A032701
- Sort then Add, a(1)=13.at n=9A033897
- Number of binary [ n,5 ] codes of dimension <= 5 without zero columns.at n=11A034339
- Numerators of continued fraction convergents to sqrt(246).at n=6A041460
- Numbers having four 1's in base 8.at n=15A043428
- p, p+2 and p+8 are primes.at n=38A046134