668390 has 16 divisors (see below), whose sum is σ = 1218240. Its totient is φ = 264000.

The previous prime is 668347. The next prime is 668407. The reversal of 668390 is 93866.

It is a happy number.

668390 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

668390 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, 515 + ... + 1265.

It is an arithmetic number, because the mean of its divisors is an integer number (76140).

2⁶⁶⁸³⁹⁰ is an apocalyptic number.

668390 is a deficient number, since it is larger than the sum of its proper divisors (549850).

668390 is a wasteful number, since it uses less digits than its factorization.

668390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 847.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 668390 is about 817.5512216369. The cubic root of 668390 is about 87.4332552226.

The spelling of 668390 in words is "six hundred sixty-eight thousand, three hundred ninety".