215
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 8
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 264
- Proper Divisor Sum (Aliquot Sum)
- 49
- 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
- 168
- Möbius Function
- 1
- Radical
- 215
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 101
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
Names
- German
- zweihundertfünfzehn· ordinal: zweihundertfünfzehnste
- English
- two hundred fifteen· ordinal: two hundred fifteenth
- Spanish
- doscientos quince· ordinal: 215º
- French
- deux cent quinze· ordinal: deux cent quinzième
- Italian
- duecentoquindici· ordinal: 215º
- Latin
- ducenti quindecim· ordinal: 215.
- Portuguese
- duzentos e quinze· ordinal: 215º
Appears in sequences
- Local stops on New York City 1 Train (Broadway-7 Avenue Local) subway.at n=24A000053
- Numbers k such that (2k)^4 + 1 is prime.at n=52A000059
- Number of trees of diameter 4.at n=16A000094
- A Beatty sequence: [ n(e+1) ].at n=57A000572
- Related to S(n), the number of self-dual monotone Boolean functions of n variables (A001206): 2^n-th term is S(n).at n=20A001087
- Number of (unordered) ways of making change for n cents using coins of 2, 5 (two kinds), 10, 20, 50 cents.at n=62A001314
- Number of (unordered) ways of making change for n cents using coins of 2, 5 (two kinds), 10, 20, 50 cents.at n=60A001314
- Number of (unordered) ways of making change for n cents using coins of 2, 5 (two kinds), 10, 20, 50 cents.at n=64A001314
- Numbers whose digits contain no loops (version 2).at n=58A001742
- Primes multiplied by 5.at n=13A001750
- Beatty sequence of (5+sqrt(13))/2.at n=49A001956
- v-pile positions of the 4-Wythoff game with i=1.at n=41A001964
- 9th powers written backwards.at n=20A002239
- 9th powers written backwards.at n=2A002239
- Numbers m such that m^2 + m + 1 is prime.at n=60A002384
- Earliest sequence with a(a(n))=5n.at n=44A002518
- Number of unrooted triangulations of a disk that have reflection symmetry with n interior nodes and 3 nodes on the boundary.at n=7A002712
- Numbers m such that 6m-1, 6m+1 are twin primes.at n=42A002822
- Egyptian fractions: number of solutions of 1 = 1/x_1 + ... + 1/x_n in positive integers.at n=3A002967
- Number of n-node trees with a forbidden limb of length 5.at n=11A002991