166081409 has 16 divisors (see below), whose sum is σ = 185434368. Its totient is φ = 147768192.

The previous prime is 166081393. The next prime is 166081417. The reversal of 166081409 is 904180661.

It is not a de Polignac number, because 166081409 - 2⁴ = 166081393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166081009) 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 15 ways as a sum of consecutive naturals, for example, 38909 + ... + 42965.

It is an arithmetic number, because the mean of its divisors is an integer number (11589648).

Almost surely, 2^166081409 is an apocalyptic number.

It is an amenable number.

166081409 is a deficient number, since it is larger than the sum of its proper divisors (19352959).

166081409 is a wasteful number, since it uses less digits than its factorization.

166081409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4184.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 166081409 is about 12887.2576213871. The cubic root of 166081409 is about 549.6762932638.

The spelling of 166081409 in words is "one hundred sixty-six million, eighty-one thousand, four hundred nine".