166888661 has 2 divisors, whose sum is σ = 166888662. Its totient is φ = 166888660.

The previous prime is 166888651. The next prime is 166888669.

It is a happy number.

166888661 is nontrivially palindromic in base 10.

166888661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138062500 + 28826161 = 11750^2 + 5369^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 166888661 - 2¹⁸ = 166626517 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166888669) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83444330 + 83444331.

It is an arithmetic number, because the mean of its divisors is an integer number (83444331).

Almost surely, 2^166888661 is an apocalyptic number.

It is an amenable number.

166888661 is a deficient number, since it is larger than the sum of its proper divisors (1).

166888661 is an equidigital number, since it uses as much as digits as its factorization.

166888661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 663552, while the sum is 50.

The square root of 166888661 is about 12918.5394298272. The cubic root of 166888661 is about 550.5654361262.

The spelling of 166888661 in words is "one hundred sixty-six million, eight hundred eighty-eight thousand, six hundred sixty-one".