165456509 has 2 divisors, whose sum is σ = 165456510. Its totient is φ = 165456508.

The previous prime is 165456493. The next prime is 165456539. The reversal of 165456509 is 905654561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 150749284 + 14707225 = 12278^2 + 3835^2 .

It is a cyclic number.

It is not a de Polignac number, because 165456509 - 2⁴ = 165456493 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165456539) by changing a digit.

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 as a sum of consecutive naturals, namely, 82728254 + 82728255.

It is an arithmetic number, because the mean of its divisors is an integer number (82728255).

Almost surely, 2^165456509 is an apocalyptic number.

It is an amenable number.

165456509 is a deficient number, since it is larger than the sum of its proper divisors (1).

165456509 is an equidigital number, since it uses as much as digits as its factorization.

165456509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162000, while the sum is 41.

The square root of 165456509 is about 12862.9898934890. The cubic root of 165456509 is about 548.9860204823.

The spelling of 165456509 in words is "one hundred sixty-five million, four hundred fifty-six thousand, five hundred nine".