668218 has 16 divisors (see below), whose sum is σ = 1065960. Its totient is φ = 313600.

The previous prime is 668209. The next prime is 668221. The reversal of 668218 is 812866.

668218 is nontrivially palindromic in base 16.

It can be written as a sum of positive squares in 4 ways, for example, as 471969 + 196249 = 687^2 + 443^2 .

It is a super-3 number, since 3×668218³ = 895108673233368696, which contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 668218.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2238 + ... + 2518.

2⁶⁶⁸²¹⁸ is an apocalyptic number.

668218 is a deficient number, since it is larger than the sum of its proper divisors (397742).

668218 is a wasteful number, since it uses less digits than its factorization.

668218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353.

The product of its digits is 4608, while the sum is 31.

The square root of 668218 is about 817.4460226828. The cubic root of 668218 is about 87.4257547065.

The spelling of 668218 in words is "six hundred sixty-eight thousand, two hundred eighteen".