663663 has 48 divisors (see below), whose sum is σ = 1264896. Its totient is φ = 299520.

The previous prime is 663661. The next prime is 663683. The reversal of 663663 is 366366.

663663 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 663663 - 2¹ = 663661 is a prime.

663663 is strictly pandigital in base 7.

It is a self number, because there is not a number n which added to its sum of digits gives 663663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663661) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 39031 + ... + 39047.

It is an arithmetic number, because the mean of its divisors is an integer number (26352).

2⁶⁶³⁶⁶³ is an apocalyptic number.

663663 is a deficient number, since it is larger than the sum of its proper divisors (601233).

663663 is a wasteful number, since it uses less digits than its factorization.

663663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64 (or 51 counting only the distinct ones).

The product of its digits is 11664, while the sum is 30.

The square root of 663663 is about 814.6551417625. The cubic root of 663663 is about 87.2266517165.

It can be divided in two parts, 663 and 663, that added together give a triangular number (1326 = T₅₁).

The spelling of 663663 in words is "six hundred sixty-three thousand, six hundred sixty-three".