660009 has 16 divisors (see below), whose sum is σ = 1026432. Its totient is φ = 369408.

The previous prime is 660001. The next prime is 660013. The reversal of 660009 is 900066.

It is not a de Polignac number, because 660009 - 2³ = 660001 is a prime.

It is a super-2 number, since 2×660009² = 871223760162, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (660001) 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 15 ways as a sum of consecutive naturals, for example, 817 + ... + 1409.

It is an arithmetic number, because the mean of its divisors is an integer number (64152).

2⁶⁶⁰⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

660009 is a deficient number, since it is larger than the sum of its proper divisors (366423).

660009 is a wasteful number, since it uses less digits than its factorization.

660009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656.

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

The square root of 660009 is about 812.4093795618. The cubic root of 660009 is about 87.0662726639.

The spelling of 660009 in words is "six hundred sixty thousand, nine".