720668 has 12 divisors (see below), whose sum is σ = 1358280. Its totient is φ = 332592.

The previous prime is 720661. The next prime is 720677. The reversal of 720668 is 866027.

It is a self number, because there is not a number n which added to its sum of digits gives 720668.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720661) by changing a digit.

720668 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 (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6878 + ... + 6981.

It is an arithmetic number, because the mean of its divisors is an integer number (113190).

2⁷²⁰⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

720668 is a deficient number, since it is larger than the sum of its proper divisors (637612).

720668 is a wasteful number, since it uses less digits than its factorization.

720668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13876 (or 13874 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 720668 is about 848.9216689424. The cubic root of 720668 is about 89.6558046817.

The spelling of 720668 in words is "seven hundred twenty thousand, six hundred sixty-eight".