165906609 has 12 divisors (see below), whose sum is σ = 243147408. Its totient is φ = 100549240.

The previous prime is 165906581. The next prime is 165906617. The reversal of 165906609 is 906609561.

It is not a de Polignac number, because 165906609 - 2⁸ = 165906353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165906619) 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 11 ways as a sum of consecutive naturals, for example, 228159 + ... + 228884.

It is an arithmetic number, because the mean of its divisors is an integer number (20262284).

Almost surely, 2^165906609 is an apocalyptic number.

It is an amenable number.

165906609 is a deficient number, since it is larger than the sum of its proper divisors (77240799).

165906609 is a wasteful number, since it uses less digits than its factorization.

165906609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457068 (or 457057 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 42.

The square root of 165906609 is about 12880.4739431436. The cubic root of 165906609 is about 549.4833815557.

The spelling of 165906609 in words is "one hundred sixty-five million, nine hundred six thousand, six hundred nine".