15641
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15642
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15640
- Möbius Function
- -1
- Radical
- 15641
- 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
- 107
- 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
- 1823
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that 19*2^k - 1 is prime.at n=23A001775
- Prime quadruples: numbers k such that k, k+2, k+6, k+8 are all prime.at n=13A007530
- a(n) = n OR n^3 (applied to binary expansions).at n=24A008468
- a(n) = n^(n+1) + (n-1)^2.at n=5A029711
- Initial terms of '4-block' primes as described in A032591.at n=21A032592
- Start of a string of exactly 2 consecutive (but disjoint) pairs of twin primes.at n=32A035790
- Number of partitions in parts not of the form 23k, 23k+1 or 23k-1. Also number of partitions with no part of size 1 and differences between parts at distance 10 are greater than 1.at n=45A035989
- Number of 5-valent trees with n nodes.at n=16A036650
- Primes at which the difference pattern X,2,4,2,Y (X and Y >= 6) occurs in A001223.at n=6A052165
- Numbers n for which there are exactly five k such that n = k + reverse(k).at n=35A072429
- Prime(prime(n)) when prime(prime(n)) and n are twin primes.at n=16A087394
- Numbers k such that k + (largest digit of k)! is a palindromic prime.at n=10A095920
- "Secondary twin primes": a(n) = A006450(A096477(n)).at n=36A096479
- Values of n for which the decimal number 10...030...01 is an n-digit prime.at n=19A100028
- Primes of the form a^4 + b^3 with b>0.at n=31A100271
- Primes p equal to the sum of two successive sexy primes + 1 such that p + 6 is also prime.at n=26A104043
- Prime numbers p such that p+6, p^2+6^2, p^4+6^4 are all primes.at n=10A107441
- Prime Friedman numbers.at n=7A112419
- a(n) = 3 + floor((2 + Sum_{j=1..n-1} a(j))/5).at n=47A120172
- Primes congruent to 32 mod 43.at n=38A142281