663946 has 4 divisors (see below), whose sum is σ = 995922. Its totient is φ = 331972.

The previous prime is 663937. The next prime is 663959. The reversal of 663946 is 649366.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 474721 + 189225 = 689^2 + 435^2 .

It is an unprimeable number.

663946 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165985 + ... + 165988.

2⁶⁶³⁹⁴⁶ is an apocalyptic number.

663946 is a deficient number, since it is larger than the sum of its proper divisors (331976).

663946 is a wasteful number, since it uses less digits than its factorization.

663946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331975.

The product of its digits is 23328, while the sum is 34.

The square root of 663946 is about 814.8288163780. The cubic root of 663946 is about 87.2390483869.

The spelling of 663946 in words is "six hundred sixty-three thousand, nine hundred forty-six".