1627
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
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1628
- 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
- 1626
- Möbius Function
- -1
- Radical
- 1627
- 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
- 73
- 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
- 258
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/3.at n=21A001133
- Numbers k such that phi(2k+1) < phi(2k).at n=20A001837
- Numerators of coefficients of log(1+x)/sqrt(1+x).at n=5A002549
- Number of binary vectors with restricted repetitions.at n=9A003440
- Erroneous version of A028491.at n=8A004060
- Class 4+ primes (for definition see A005105).at n=27A005108
- Primes p such that 2p-1 is also prime.at n=46A005382
- Prime self (or Colombian) numbers: primes not expressible as the sum of an integer and its digit sum.at n=28A006378
- From relations between Siegel theta series.at n=14A006476
- Where the prime race among 7k+1, ..., 7k+6 changes leader.at n=15A007354
- Coordination sequence T3 for Zeolite Code AFS and BPH.at n=31A008025
- Coordination sequence T1 for Zeolite Code LOV.at n=27A008134
- Coordination sequence T4 for Zeolite Code NES.at n=26A008208
- Coordination sequence T1 for Zeolite Code VFI.at n=31A008245
- Primes of the form x^2 + 27y^2.at n=35A014752
- Numbers k=3*m+1 such that 2^m == 1 (mod k).at n=36A016108
- Powers of fifth root of 7 rounded to nearest integer.at n=19A018133
- Powers of fifth root of 7 rounded up.at n=19A018134
- a(n) = Sum_{k>=1} floor( 2*(1+sqrt(2))^(n-k) ).at n=7A020963
- a(n) = [ a(n-1)/a(1) ] + [ a(n-3)/a(3) ] + [ a(n-5)/a(5) ] + ..., for n >= 3.at n=31A022872