7225
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 9
- Divisor Sum
- 9517
- Proper Divisor Sum (Aliquot Sum)
- 2292
- 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
- 5440
- Möbius Function
- 0
- Radical
- 85
- Omega Function (Ω)
- 4
- 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
- yes
- 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
- 44
- 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
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Discriminants of totally real quartic fields (see comments).at n=23A002769
- Number of inequivalent ways to color vertices of a regular tetrahedron using <= n colors.at n=17A006008
- Crystal ball sequence for D_4 lattice.at n=6A007204
- a(n) = (2*n - 9)*n^2.at n=17A015243
- Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers.at n=42A016754
- a(n) = (3*n+1)^2.at n=28A016778
- a(n) = (4*n + 1)^2.at n=21A016814
- a(n) = (5*n)^2.at n=17A016850
- a(n) = (6*n + 1)^2.at n=14A016922
- a(n) = (7*n + 1)^2.at n=12A016994
- a(n) = (8*n + 5)^2.at n=10A017126
- a(n) = (9*n + 4)^2.at n=9A017210
- a(n) = (10*n + 5)^2.at n=8A017330
- a(n) = (11*n + 8)^2.at n=7A017486
- a(n) = (12*n + 1)^2.at n=7A017534
- Expansion of 1/(1-x^3-x^4-x^5-x^6-x^7).at n=30A017820
- Numbers k that are the sum of m nonzero squares for all 1 <= m <= k - 14.at n=29A018820
- Define {b(n)} by b(1) = 3, b(n) (n >= 2) is smallest number such that b(1)^2 + ... + b(n)^2 = m^2 for some m and all b(i) are distinct. Sequence gives values of m^2.at n=3A018929
- a(n) is the smallest square that is the sum of n distinct positive squares.at n=26A018936
- Discriminants of totally real quartic fields.at n=30A023680