Subtracting from 647 its sum of digits (17), we obtain a triangular number (630 = T35).
Subtracting 647 from its reverse (746), we obtain a palindrome (99).
647 is nontrivially palindromic in base 14 and base 15.
647 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
647 is an esthetic number in base 14, because in such base its adjacent digits differ by 1.
It is a weak prime.
647 is a truncatable prime.
It is a cyclic number.
It is a Chen prime.
It is a magnanimous number.
647 is an undulating number in base 14 and base 15.
It is a plaindrome in base 6, base 9, base 12 and base 13.
It is a congruent number.
2647 is an apocalyptic number.
647 is an equidigital number, since it uses as much as digits as its factorization.
647 is an odious number, because the sum of its binary digits is odd.
The square root of 647 is about 25.4361946840. The cubic root of 647 is about 8.6490437425.
The spelling of 647 in words is "six hundred forty-seven", and thus it is an aban number.