667665566766 has 144 divisors (see below), whose sum is σ = 1649237937984. Its totient is φ = 194903280000.

The previous prime is 667665566761. The next prime is 667665566783.

667665566766 is a `hidden beast` number, since 6 + 6 + 7 + 6 + 6 + 556 + 6 + 7 + 66 = 666.

667665566766 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 667665566694 and 667665566703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667665566761) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8098171 + ... + 8180201.

It is an arithmetic number, because the mean of its divisors is an integer number (11453041236).

Almost surely, 2^667665566766 is an apocalyptic number.

667665566766 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 667665566766, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (824618968992).

667665566766 is an abundant number, since it is smaller than the sum of its proper divisors (981572371218).

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

667665566766 is a wasteful number, since it uses less digits than its factorization.

667665566766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82199 (or 82185 counting only the distinct ones).

The product of its digits is 2057529600, while the sum is 72.

The spelling of 667665566766 in words is "six hundred sixty-seven billion, six hundred sixty-five million, five hundred sixty-six thousand, seven hundred sixty-six".