165509406 has 20 divisors (see below), whose sum is σ = 370864032. Its totient is φ = 55169748.

The previous prime is 165509389. The next prime is 165509413. The reversal of 165509406 is 604905561.

165509406 is a `hidden beast` number, since 16 + 550 + 94 + 0 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 510670 + ... + 510993.

Almost surely, 2^165509406 is an apocalyptic number.

165509406 is an abundant number, since it is smaller than the sum of its proper divisors (205354626).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165509406 is a wasteful number, since it uses less digits than its factorization.

165509406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1021677 (or 1021668 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 165509406 is about 12865.0458996461. The cubic root of 165509406 is about 549.0445184718.

The spelling of 165509406 in words is "one hundred sixty-five million, five hundred nine thousand, four hundred six".