166365509 has 4 divisors (see below), whose sum is σ = 173598816. Its totient is φ = 159132204.

The previous prime is 166365473. The next prime is 166365517. The reversal of 166365509 is 905563661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166365509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166365559) 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, 3616619 + ... + 3616664.

It is an arithmetic number, because the mean of its divisors is an integer number (43399704).

Almost surely, 2^166365509 is an apocalyptic number.

It is an amenable number.

166365509 is a deficient number, since it is larger than the sum of its proper divisors (7233307).

166365509 is an equidigital number, since it uses as much as digits as its factorization.

166365509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7233306.

The product of its (nonzero) digits is 145800, while the sum is 41.

The square root of 166365509 is about 12898.2754273585. The cubic root of 166365509 is about 549.9895413989.

The spelling of 166365509 in words is "one hundred sixty-six million, three hundred sixty-five thousand, five hundred nine".