668397 has 4 divisors (see below), whose sum is σ = 891200. Its totient is φ = 445596.

The previous prime is 668347. The next prime is 668407. The reversal of 668397 is 793866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 668397 - 2⁸ = 668141 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668347) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 111397 + ... + 111402.

It is an arithmetic number, because the mean of its divisors is an integer number (222800).

2⁶⁶⁸³⁹⁷ is an apocalyptic number.

It is an amenable number.

668397 is a deficient number, since it is larger than the sum of its proper divisors (222803).

668397 is a wasteful number, since it uses less digits than its factorization.

668397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222802.

The product of its digits is 54432, while the sum is 39.

The square root of 668397 is about 817.5555027030. Note that the first 4 decimals coincide. The cubic root of 668397 is about 87.4335604490.

The spelling of 668397 in words is "six hundred sixty-eight thousand, three hundred ninety-seven".