666306 has 28 divisors (see below), whose sum is σ = 1501782. Its totient is φ = 221616.

The previous prime is 666301. The next prime is 666329. The reversal of 666306 is 603666.

It can be written as a sum of positive squares in only one way, i.e., 455625 + 210681 = 675^2 + 459^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 666306.

It is not an unprimeable number, because it can be changed into a prime (666301) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 1230 + ... + 1686.

2⁶⁶⁶³⁰⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666306, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (750891).

666306 is an abundant number, since it is smaller than the sum of its proper divisors (835476).

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

666306 is an equidigital number, since it uses as much as digits as its factorization.

666306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477 (or 462 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 27.

The square root of 666306 is about 816.2756887229. The cubic root of 666306 is about 87.3422900642.

The spelling of 666306 in words is "six hundred sixty-six thousand, three hundred six".