166151809 has 4 divisors (see below), whose sum is σ = 166214916. Its totient is φ = 166088704.

The previous prime is 166151801. The next prime is 166151813. The reversal of 166151809 is 908151661.

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

It can be written as a sum of positive squares in 2 ways, for example, as 80496784 + 85655025 = 8972^2 + 9255^2 .

It is a cyclic number.

It is not a de Polignac number, because 166151809 - 2³ = 166151801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166151801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27424 + ... + 32929.

It is an arithmetic number, because the mean of its divisors is an integer number (41553729).

Almost surely, 2^166151809 is an apocalyptic number.

It is an amenable number.

166151809 is a deficient number, since it is larger than the sum of its proper divisors (63107).

166151809 is an equidigital number, since it uses as much as digits as its factorization.

166151809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63106.

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 166151809 is about 12889.9887121750. The cubic root of 166151809 is about 549.7539494462.

The spelling of 166151809 in words is "one hundred sixty-six million, one hundred fifty-one thousand, eight hundred nine".