166786666 has 4 divisors (see below), whose sum is σ = 250180002. Its totient is φ = 83393332.

The previous prime is 166786663. The next prime is 166786667. The reversal of 166786666 is 666687661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666687661 = 4481 ⋅148781.

It can be written as a sum of positive squares in only one way, i.e., 88906041 + 77880625 = 9429^2 + 8825^2 .

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (166786663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41696665 + ... + 41696668.

Almost surely, 2^166786666 is an apocalyptic number.

166786666 is a deficient number, since it is larger than the sum of its proper divisors (83393336).

166786666 is an equidigital number, since it uses as much as digits as its factorization.

166786666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83393335.

The product of its digits is 2612736, while the sum is 52.

The square root of 166786666 is about 12914.5912052995. The cubic root of 166786666 is about 550.4532528198.

The spelling of 166786666 in words is "one hundred sixty-six million, seven hundred eighty-six thousand, six hundred sixty-six".