7557
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11040
- Proper Divisor Sum (Aliquot Sum)
- 3483
- 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
- 4560
- Möbius Function
- -1
- Radical
- 7557
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 83
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Base-10 palindromes that start with 7.at n=17A043042
- Palindromes with exactly 3 prime factors (counted with multiplicity).at n=46A046329
- Palindromes with exactly 3 distinct prime factors.at n=31A046393
- Palindromes that are the sum of the first n palindromes for some n.at n=5A046488
- Sum of the first n palindromes (A002113).at n=46A046489
- Number of asymmetric (identity) trees with n nodes and 4 leaves.at n=30A055335
- a(1) = 1; a(n) = smallest multiple of n-th prime (n>1) with all odd digits.at n=49A062280
- Palindromic odd composite numbers that are the products of an odd number of distinct primes.at n=16A075808
- Palindromic odd numbers with exactly 3 prime factors (counted with multiplicity).at n=25A075814
- Palindromic odd composite numbers with an odd number of prime factors (counted with multiplicity).at n=27A075815
- Palindromes not divisible by any of their digits.at n=44A082947
- Palindromes neither divisible by any of their digits nor by the sum of their digits.at n=42A082948
- Palindromes made of only prime digits.at n=38A084983
- p such that p^4 + q^4 = r^4 + s^4 = a(n).at n=22A088728
- a(n) is the minimal area of a convex lattice polygon with 2n sides.at n=36A089187
- a(n) is the decimal expansion of 7nn7.at n=5A100897
- a(1) = 1, then the rearrangement of odd palindromes such that every concatenation is a prime for n > 1.at n=31A113578
- Start with 1 and repeatedly reverse the digits and add 56 to get the next term.at n=16A118152
- Odd palindromes with an even number of digits.at n=40A132285
- a(n) = n*(7*n-2).at n=33A135703