668636 has 6 divisors (see below), whose sum is σ = 1170120. Its totient is φ = 334316.

The previous prime is 668623. The next prime is 668671. The reversal of 668636 is 636866.

It is a junction number, because it is equal to n+sod(n) for n = 668596 and 668605.

It is a congruent number.

It is an unprimeable number.

668636 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 (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83576 + ... + 83583.

It is an arithmetic number, because the mean of its divisors is an integer number (195020).

2⁶⁶⁸⁶³⁶ is an apocalyptic number.

It is an amenable number.

668636 is a deficient number, since it is larger than the sum of its proper divisors (501484).

668636 is a wasteful number, since it uses less digits than its factorization.

668636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167163 (or 167161 counting only the distinct ones).

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

The square root of 668636 is about 817.7016570853. The cubic root of 668636 is about 87.4439804692.

The spelling of 668636 in words is "six hundred sixty-eight thousand, six hundred thirty-six".