663866 has 8 divisors (see below), whose sum is σ = 1138080. Its totient is φ = 284508.

The previous prime is 663857. The next prime is 663869. The reversal of 663866 is 668366.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a nialpdrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (663869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23696 + ... + 23723.

It is an arithmetic number, because the mean of its divisors is an integer number (142260).

2⁶⁶³⁸⁶⁶ is an apocalyptic number.

663866 is a deficient number, since it is larger than the sum of its proper divisors (474214).

663866 is a wasteful number, since it uses less digits than its factorization.

663866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47428.

The product of its digits is 31104, while the sum is 35.

The square root of 663866 is about 814.7797248337. The cubic root of 663866 is about 87.2355443850.

The spelling of 663866 in words is "six hundred sixty-three thousand, eight hundred sixty-six".