2520
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 9360
- Proper Divisor Sum (Aliquot Sum)
- 6840
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 576
- Möbius Function
- 0
- Radical
- 210
- Omega Function (Ω)
- 7
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 40
- 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
- Number of 3-line Latin rectangles.at n=2A000536
- Number of labeled rooted trees of height 4 with n nodes.at n=1A000553
- a(n) = (2n)!/2^n.at n=4A000680
- Landau's function g(n): largest order of permutation of n elements. Equivalently, largest LCM of partitions of n.at n=29A000793
- Exponential generating function: 2*(1+3*x)/(1-2*x)^(7/2).at n=3A000906
- a(n) = (2n+3)! /( n! * (n+1)! ).at n=3A000911
- Orders of noncyclic simple groups (without repetition).at n=7A001034
- a(0)=12; thereafter a(n) = 12 times the product of the first n primes.at n=4A001041
- Triangle of Narayana numbers T(n,k) = C(n-1,k-1)*C(n,k-1)/k with 1 <= k <= n, read by rows. Also called the Catalan triangle.at n=51A001263
- Triangle of Narayana numbers T(n,k) = C(n-1,k-1)*C(n,k-1)/k with 1 <= k <= n, read by rows. Also called the Catalan triangle.at n=48A001263
- Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^9 in powers of x.at n=14A001487
- Order of alternating group A_n, or number of even permutations of n letters.at n=7A001710
- a(n) = 4*(2n+1)!/n!^2.at n=4A002011
- High temperature series for spin-1/2 Heisenberg specific heat on 3-dimensional simple cubic lattice.at n=4A002169
- Highly composite numbers: numbers n where d(n), the number of divisors of n (A000005), increases to a record.at n=17A002182
- Superior highly composite numbers: positive integers n for which there is an e > 0 such that d(n)/n^e >= d(k)/k^e for all k > 1, where the function d(n) counts the divisors of n (A000005).at n=6A002201
- Order of largest (finite) group with n conjugacy classes.at n=8A002319
- Expansion of (theta_3(z)*theta_3(7z)+theta_2(z)*theta_2(7z))^3.at n=19A002653
- Theta series of 6-dimensional lattice A_6^(2) (other names for this lattice or the corresponding quadratic form are LAMBDA_{3,lambda}, P_6^(5), phi_6, F_14).at n=19A002706
- a(n) = denominator of harmonic number H(n) = Sum_{i=1..n} 1/i.at n=8A002805