166211609 has 2 divisors, whose sum is σ = 166211610. Its totient is φ = 166211608.

The previous prime is 166211597. The next prime is 166211623. The reversal of 166211609 is 906112661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125507209 + 40704400 = 11203^2 + 6380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166211609 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (166211629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83105804 + 83105805.

It is an arithmetic number, because the mean of its divisors is an integer number (83105805).

Almost surely, 2^166211609 is an apocalyptic number.

It is an amenable number.

166211609 is a deficient number, since it is larger than the sum of its proper divisors (1).

166211609 is an equidigital number, since it uses as much as digits as its factorization.

166211609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 166211609 is about 12892.3081331467. The cubic root of 166211609 is about 549.8198958501.

The spelling of 166211609 in words is "one hundred sixty-six million, two hundred eleven thousand, six hundred nine".