7531
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
- 4
- Divisor Sum
- 7992
- Proper Divisor Sum (Aliquot Sum)
- 461
- 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
- 7072
- Möbius Function
- 1
- Radical
- 7531
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 62
- Smith Number
- no
- 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
- Number of nonzero coefficients of order n in Baker-Campbell-Hausdorff expansion.at n=15A005489
- a(n) = n*(13*n + 1)/2.at n=34A022271
- n written in fractional base 9/7.at n=28A024655
- Prefix primes in base 8 (written in base 8).at n=42A024768
- Number of partitions of n with equal number of parts congruent to each of 0 and 1 (mod 4).at n=45A035540
- Number of partitions of n into parts not of the form 25k, 25k+7 or 25k-7. Also number of partitions with at most 6 parts of size 1 and differences between parts at distance 11 are greater than 1.at n=32A036006
- Concatenation of the first n odd numbers in reverse order.at n=3A038395
- Smallest multiple of 2n+1 with the property that its digits are odd and each digit is two less (mod 10) than the previous digit, or 0 if no such number exists.at n=8A062887
- Numbers k such that both k and the k-th prime have nonincreasing digits.at n=43A116067
- Odd digits in decreasing order.at n=25A119252
- Least positive k such that 10^n + {k, k+2, k+6, k+8} are all prime.at n=11A121066
- Generalized Narayana triangle for secant.at n=40A180959
- Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 n X 2 array.at n=16A219621
- Start with 1. Successive digits in the sequence must differ by 2. Adjoin the smallest number not yet in the sequence.at n=25A228328
- Semiprimes with digits in strictly decreasing order.at n=48A235108
- 9-distance Pell numbers.at n=49A237718
- Semiprimes with digits in descending order that differ exactly by 2.at n=5A245044
- Reverse concatenation of distinct digits of all divisors of n in base 10.at n=34A256824
- Numbers n such that n!3 + 3^9 is prime, where n!3 = n!!! is a triple factorial number (A007661).at n=38A265378
- Positive integers with digits in decreasing order that differ by 2.at n=24A290951