66666666 is nontrivially palindromic in base 10.
66666666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a nude number because it is divisible by every one of its digits.
66666666 is a nontrivial repdigit in base 10.
It is a plaindrome in base 10.
It is a nialpdrome in base 10.
It is a zygodrome in base 10.
Almost surely, 266666666 is an apocalyptic number.
66666666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.
It is a practical number, because each smaller number is the sum of distinct divisors of 66666666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74996928).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
66666666 is a wasteful number, since it uses less digits than its factorization.
66666666 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 327.
The square root of 66666666 is about 8164.9657684524. The cubic root of 66666666 is about 405.4801316866.
The spelling of 66666666 in words is "sixty-six million, six hundred sixty-six thousand, six hundred sixty-six".