66009 has 4 divisors (see below), whose sum is σ = 88016. Its totient is φ = 44004.

The previous prime is 65993. The next prime is 66029. The reversal of 66009 is 90066.

66009 is nontrivially palindromic in base 5.

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 not a de Polignac number, because 66009 - 2⁴ = 65993 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10999 + ... + 11004.

It is an arithmetic number, because the mean of its divisors is an integer number (22004).

2⁶⁶⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

66009 is a deficient number, since it is larger than the sum of its proper divisors (22007).

66009 is a wasteful number, since it uses less digits than its factorization.

66009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22006.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 66009 is about 256.9221672024. The cubic root of 66009 is about 40.4142370500.

The spelling of 66009 in words is "sixty-six thousand, nine".