16421
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 16422
- 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
- 16420
- Möbius Function
- -1
- Radical
- 16421
- 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
- 159
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1903
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers whose base-4 representation contains exactly four 0's and three 1's.at n=19A045036
- Primes p from A031924 such that A052180(primepi(p)) = 11.at n=34A052232
- Primes p+2^n arising in A056206.at n=14A056208
- Number of step cyclic shifted sequence structures using exactly four different symbols.at n=12A056436
- Number of primitive (period n) step cyclic shifted sequence structures using exactly four different symbols.at n=12A056446
- Negative numbers written in a bits-of-Pi/primorial base system.at n=10A109839
- Beginning with 2, primes of the form: least multiple of the previous term followed by a 1. Beginning with 2, a(n) is the least prime of the form k*a(n-1)*10 + 1.at n=3A112767
- Least prime P1 of 8 different primes: 4 consecutive primes P1 P2 P3 P4 and 4 primes Q1 Q2 Q3 Q4 such that Q1 with same digits than P1 if not 6 or 9, if 6 then replace with 9 and if 9 then replace with 6, same for Q2 from P2 Q3 from P3 and Q4 from P4.at n=2A122713
- Prime arithmetic mean of ten consecutive primes.at n=36A123096
- Left truncatable primes in base 9 (written in decimal form).at n=46A129945
- Numbers n with property that for each single digit d of n, we can also see the decimal expansion of 2^d as a substring of n. Also n may not contain any zero digits.at n=6A135016
- Numbers k such that k and k^2 use only the digits 1, 2, 4, 6 and 9.at n=36A136995
- Prime numbers appearing in A139033.at n=7A139034
- Primes congruent to 21 mod 41.at n=40A142218
- Primes congruent to 18 mod 47.at n=40A142369
- Primes congruent to 44 mod 53.at n=36A142574
- Primes congruent to 19 mod 59.at n=33A142746
- Primes congruent to 12 mod 61.at n=34A142810
- Primes p such that p1=Floor[p/2]+p is prime and p2=Ceiling[p1/2]+p1 is prime.at n=36A158712
- Largest prime appearing as an exponent in the sum in A159261.at n=8A159262