Number of the day: 3641

Properties of the number 3641:

3641 = 11 × 331 is semiprime and squarefree.
3641 has 2 distinct prime factors, 4 divisors, 7 antidivisors and 3300 totatives.
3641 has a semiprime digit sum 14 in base 10.
3641 has an oblong digit product 72 in base 10.
Reversing the decimal digits of 3641 results in a sphenic number.
3641 = 1821² - 1820² = 171² - 160² is the difference of 2 nonnegative squares in 2 ways.
3641 is the difference of 2 positive pentagonal numbers in 2 ways.
3641 = 4² + 5² + 60² is the sum of 3 positive squares.
3641² is the sum of 3 positive squares.
3641 is a proper divisor of 661² - 1.
3641 = '3' + '641' is the concatenation of 2 prime numbers.
3641 is an emirpimes in (at least) the following bases: 4, 6, 7, 9, 14, 18, 23, 27, 30, 31, 32, 40, 42, 44, 45, 46, 47, 49, 50, 55, 57, 59, 60, 63, 65, 66, 68, 70, 74, 81, 83, 84, 85, 89, 92, 95, and 98.
3641 is palindromic in (at least) the following bases: 21, 34, 52, 56, -2, -8, -23, -65, -70, and -91.
3641 in base 3 = 11222212 and consists of only the digits '1' and '2'.
3641 in base 21 = 858 and consists of only the digits '5' and '8'.
3641 in base 22 = 7bb and consists of only the digits '7' and 'b'.
3641 in base 33 = 3bb and consists of only the digits '3' and 'b'.
3641 in base 34 = 353 and consists of only the digits '3' and '5'.
3641 in base 42 = 22T and consists of only the digits '2' and 'T'.
3641 in base 51 = 1KK and consists of only the digits '1' and 'K'.
3641 in base 52 = 1I1 and consists of only the digits '1' and 'I'.
3641 in base 55 = 1BB and consists of only the digits '1' and 'B'.
3641 in base 56 = 191 and consists of only the digits '1' and '9'.

The number 3641 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A001701: Generalized Stirling numbers.
A005915: Hexagonal prism numbers: a(n) = (n + 1)*(3*n^2 + 3*n + 1).
A006322: 4-dimensional analog of centered polygonal numbers.
A015565: a(n) = 7*a(n-1) + 8*a(n-2), a(0) = 0, a(1) = 1.
A046063: Numbers n such that n-th partition number A000041(n) is prime.
A056106: Second spoke of a hexagonal spiral.
A060884: a(n) = n^4 - n^3 + n^2 - n + 1.
A113405: Expansion of x^3/(1-2*x+x^3-2*x^4) = x^3/( (1-2*x)*(1+x)*(1-x+x^2) ).
A116520: a(0) = 0, a(1) = 1; a(n) = max { 4*a(k)+a(n-k) | 1 <= k <= n/2 }, for n>1.
A194270: D-toothpick sequence of the second kind (see Comments lines for definition).