663889 has 4 divisors (see below), whose sum is σ = 665524. Its totient is φ = 662256.

The previous prime is 663881. The next prime is 663893. The reversal of 663889 is 988366.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 490000 + 173889 = 700^2 + 417^2 .

It is a cyclic number.

It is not a de Polignac number, because 663889 - 2³ = 663881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (663881) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 319 + ... + 1195.

It is an arithmetic number, because the mean of its divisors is an integer number (166381).

2⁶⁶³⁸⁸⁹ is an apocalyptic number.

It is an amenable number.

663889 is a deficient number, since it is larger than the sum of its proper divisors (1635).

663889 is an equidigital number, since it uses as much as digits as its factorization.

663889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1634.

The product of its digits is 62208, while the sum is 40.

The square root of 663889 is about 814.7938389556. The cubic root of 663889 is about 87.2365518144.

The spelling of 663889 in words is "six hundred sixty-three thousand, eight hundred eighty-nine".