666888 has 32 divisors (see below), whose sum is σ = 1714560. Its totient is φ = 216000.

The previous prime is 666871. The next prime is 666889. The reversal of 666888 is 888666.

It is a nude number because it is divisible by every one of its digits.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 513 + ... + 1263.

It is an arithmetic number, because the mean of its divisors is an integer number (53580).

2⁶⁶⁶⁸⁸⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (857280).

666888 is an abundant number, since it is smaller than the sum of its proper divisors (1047672).

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

666888 is a wasteful number, since it uses less digits than its factorization.

666888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 797 (or 793 counting only the distinct ones).

The product of its digits is 110592, while the sum is 42.

The square root of 666888 is about 816.6321081123. The cubic root of 666888 is about 87.3677130278.

The spelling of 666888 in words is "six hundred sixty-six thousand, eight hundred eighty-eight".