15405
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 26880
- Proper Divisor Sum (Aliquot Sum)
- 11475
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7488
- Möbius Function
- 1
- Radical
- 15405
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 146
- 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
- Largest number not the sum of distinct n-th-order polygonal numbers.at n=39A007419
- Conjectured formula for irreducible 6-fold Euler sums of weight 2n+16.at n=28A019459
- Group the composite numbers so that the sum of the n-th group is a multiple of the n-th prime: (4), (6), (8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22), (24, 25), (26, 27, 28, 30, 32), (33, 34, ...), ... Sequence gives sum of n-th group.at n=21A074124
- Numbers m such that pi(m) = d_1!!*d_2!!*...*d_k!! where d_1 d_2 ... d_k is the decimal expansion of m.at n=3A139182
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (-1, 1, 1), (1, -1, 0), (1, 0, 1)}.at n=9A148755
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, -1), (-1, 1, 1), (1, -1, 0), (1, 0, 1)}.at n=9A148756
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, 1), (0, 1, -1), (1, -1, 1), (1, 1, 0)}.at n=8A149311
- Nonnegative values x of solutions (x, y) to the Diophantine equation x^2 + (x+487)^2 = y^2.at n=7A207076
- Number of (2+1)X(n+1) 0..3 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with values 0..3 introduced in row major order.at n=8A231452
- Products p*q*r*s of distinct primes for which (p*q*r*s + 1)/2 is prime.at n=32A234501
- Number of unlabeled simple graphs with n vertices whose edge-set is not connected.at n=10A327235
- Number of strict integer compositions of n whose leaders of increasing runs are increasing.at n=36A376263
- Row sums of A376832.at n=14A379540
- Sum of all parts of all partitions of n with designated summands.at n=15A386998