Number of the day: 47991

Properties of the number 47991:

47991 is a cyclic number.
47991 = 3 × 17 × 941 is a sphenic number and squarefree.
47991 has 3 distinct prime factors, 8 divisors, 11 antidivisors and 30080 totatives.
47991 has a sphenic digit sum 30 in base 10.
47991 has an oblong digit sum 30 in base 10.
Reversing the decimal digits of 47991 results in a sphenic number.
47991 = 23996² - 23995² = 8000² - 7997² = 1420² - 1403² = 496² - 445² is the difference of 2 nonnegative squares in 4 ways.
47991 is the sum of 2 positive triangular numbers.
47991 is the difference of 2 positive pentagonal numbers in 2 ways.
47991 is not the sum of 3 positive squares.
47991² = 22584² + 42345² = 19425² + 43884² = 8316² + 47265² = 29580² + 37791² is the sum of 2 positive squares in 4 ways.
47991² is the sum of 3 positive squares.
47991 is a proper divisor of 577¹⁰ - 1.
47991 = '47' + '991' is the concatenation of 2 prime numbers.
47991 = '4' + '7991' is the concatenation of 2 semiprime numbers.
47991 is palindromic in (at least) the following bases: 42, -12, and -49.
47991 in base 16 = bb77 and consists of only the digits '7' and 'b'.
47991 in base 36 = 1113 and consists of only the digits '1' and '3'.
47991 in base 37 = Z22 and consists of only the digits '2' and 'Z'.
47991 in base 39 = VLL and consists of only the digits 'L' and 'V'.
47991 in base 42 = R8R and consists of only the digits '8' and 'R'.
47991 in base 48 = Kdd and consists of only the digits 'K' and 'd'.

The number 47991 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A043615: Numbers n such that base 6 representation has exactly 7 runs.
A131205: a(n) = a(n-1) + a(floor(n/2)) + a(ceiling(n/2)).
A152560: a(n) = A131205(A005578(n)).