1531
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1532
- 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
- 1530
- Möbius Function
- -1
- Radical
- 1531
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 60
- 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
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 242
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of switching networks with C(2,n) acting on domain and GL(2,Z2) acting on range.at n=2A000868
- Numbers that are the sum of 12 positive 6th powers.at n=26A003368
- a(n) = 1000*log_10(n) rounded down.at n=33A004225
- a(n) = 1000*log_10(n) rounded to the nearest integer.at n=33A004226
- Fibonacci numbers written in base 7.at n=15A004690
- Primes p such that 2p-1 is also prime.at n=44A005382
- Smallest prime beginning a complete Cunningham chain (of the second kind) of length n.at n=4A005603
- From relations between Siegel theta series.at n=10A006476
- From variance of Fibonacci search.at n=10A006479
- Where the prime race among 7k+1, ..., 7k+6 changes leader.at n=14A007354
- Primes of form 2n^2 - 2n + 19.at n=23A007639
- Coordination sequence T4 for Zeolite Code AET.at n=27A008010
- Coordination sequence T1 for Zeolite Code VNI.at n=24A009907
- Odd primes such that (3p+1)/2 and 3p+4 are also prime.at n=18A014223
- Primes p==1 (mod 6) such that 3 and -3 are both cubes (one implies other) modulo p.at n=34A014753
- Numbers k such that the continued fraction for sqrt(k) has period 58.at n=1A020397
- Primes p such that 4*p + 7 is also prime.at n=44A023215
- Numbers k such that k and 8*k + 5 are both prime.at n=49A023230
- Primes that remain prime through 2 iterations of function f(x) = 8x + 3.at n=24A023261
- Primes that remain prime through 2 iterations of function f(x) = 10x + 3.at n=34A023269