666777161777666 has 4 divisors (see below), whose sum is σ = 1000165742666502. Its totient is φ = 333388580888832.

The previous prime is 666777161777633. The next prime is 666777161777711.

666777161777666 is nontrivially palindromic in base 10.

666777161777666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 543303840236641 + 123473321541025 = 23308879^2 + 11111855^2 .

It is a super-3 number, since 3×666777161777666³ (a number of 45 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166694290444415 + ... + 166694290444418.

Almost surely, 2^{666777161777666} is an apocalyptic number.

666777161777666 is a deficient number, since it is larger than the sum of its proper divisors (333388580888836).

666777161777666 is a wasteful number, since it uses less digits than its factorization.

666777161777666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333388580888835.

The product of its digits is 32934190464, while the sum is 86.

The spelling of 666777161777666 in words is "six hundred sixty-six trillion, seven hundred seventy-seven billion, one hundred sixty-one million, seven hundred seventy-seven thousand, six hundred sixty-six".