198666 has 32 divisors (see below), whose sum is σ = 477120. Its totient is φ = 60912.

The previous prime is 198659. The next prime is 198673. The reversal of 198666 is 666891.

It is an interprime number because it is at equal distance from previous prime (198659) and next prime (198673).

198666 is a modest number, since divided by 666 gives 198 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 198666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 561 + ... + 843.

It is an arithmetic number, because the mean of its divisors is an integer number (14910).

2¹⁹⁸⁶⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 198666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (238560).

198666 is an abundant number, since it is smaller than the sum of its proper divisors (278454).

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

198666 is a wasteful number, since it uses less digits than its factorization.

198666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 301 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 198666 is about 445.7196428249. The cubic root of 198666 is about 58.3500432854.

The spelling of 198666 in words is "one hundred ninety-eight thousand, six hundred sixty-six".