668220 has 96 divisors (see below), whose sum is σ = 2247168. Its totient is φ = 145152.

The previous prime is 668209. The next prime is 668221. The reversal of 668220 is 22866.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668221) by changing a digit.

668220 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 31 ways as a sum of consecutive naturals, for example, 15519 + ... + 15561.

It is an arithmetic number, because the mean of its divisors is an integer number (23408).

2⁶⁶⁸²²⁰ is an apocalyptic number.

668220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1123584).

668220 is an abundant number, since it is smaller than the sum of its proper divisors (1578948).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

668220 is a wasteful number, since it uses less digits than its factorization.

668220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 668220 is about 817.4472460043. The cubic root of 668220 is about 87.4258419292.

It can be divided in two parts, 668 and 220, that added together give a palindrome (888).

The spelling of 668220 in words is "six hundred sixty-eight thousand, two hundred twenty".