663868 has 24 divisors (see below), whose sum is σ = 1234800. Its totient is φ = 311808.

The previous prime is 663857. The next prime is 663869. The reversal of 663868 is 868366.

It is a nialpdrome in base 7.

It is a congruent number.

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

663868 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6796 + ... + 6892.

It is an arithmetic number, because the mean of its divisors is an integer number (51450).

2⁶⁶³⁸⁶⁸ is an apocalyptic number.

It is an amenable number.

663868 is a deficient number, since it is larger than the sum of its proper divisors (570932).

663868 is a wasteful number, since it uses less digits than its factorization.

663868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189 (or 187 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 663868 is about 814.7809521583. The cubic root of 663868 is about 87.2356319885.

The spelling of 663868 in words is "six hundred sixty-three thousand, eight hundred sixty-eight".