663816 has 32 divisors (see below), whose sum is σ = 1758240. Its totient is φ = 208128.

The previous prime is 663797. The next prime is 663821. The reversal of 663816 is 618366.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

663816 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 (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406 + ... + 1221.

It is an arithmetic number, because the mean of its divisors is an integer number (54945).

2⁶⁶³⁸¹⁶ is an apocalyptic number.

It is an amenable number.

663816 is an abundant number, since it is smaller than the sum of its proper divisors (1094424).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

663816 is a wasteful number, since it uses less digits than its factorization.

663816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1653 (or 1649 counting only the distinct ones).

The product of its digits is 5184, while the sum is 30.

The square root of 663816 is about 814.7490411163. The cubic root of 663816 is about 87.2333542408.

The spelling of 663816 in words is "six hundred sixty-three thousand, eight hundred sixteen".