668849 has 4 divisors (see below), whose sum is σ = 686964. Its totient is φ = 650736.

The previous prime is 668821. The next prime is 668851. The reversal of 668849 is 948866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 948866 = 2 ⋅474433.

It can be written as a sum of positive squares in 2 ways, for example, as 628849 + 40000 = 793^2 + 200^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9002 + ... + 9075.

It is an arithmetic number, because the mean of its divisors is an integer number (171741).

2⁶⁶⁸⁸⁴⁹ is an apocalyptic number.

It is an amenable number.

668849 is a deficient number, since it is larger than the sum of its proper divisors (18115).

668849 is a wasteful number, since it uses less digits than its factorization.

668849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18114.

The product of its digits is 82944, while the sum is 41.

The square root of 668849 is about 817.8318898160. The cubic root of 668849 is about 87.4532648384.

The spelling of 668849 in words is "six hundred sixty-eight thousand, eight hundred forty-nine".