166199909 has 4 divisors (see below), whose sum is σ = 173426016. Its totient is φ = 158973804.

The previous prime is 166199881. The next prime is 166199911. The reversal of 166199909 is 909991661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166199909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166199009) 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 in 3 ways as a sum of consecutive naturals, for example, 3613019 + ... + 3613064.

It is an arithmetic number, because the mean of its divisors is an integer number (43356504).

Almost surely, 2^166199909 is an apocalyptic number.

It is an amenable number.

166199909 is a deficient number, since it is larger than the sum of its proper divisors (7226107).

166199909 is an equidigital number, since it uses as much as digits as its factorization.

166199909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7226106.

The product of its (nonzero) digits is 236196, while the sum is 50.

The square root of 166199909 is about 12891.8543662268. The cubic root of 166199909 is about 549.8069945376.

The spelling of 166199909 in words is "one hundred sixty-six million, one hundred ninety-nine thousand, nine hundred nine".