720009 has 12 divisors (see below), whose sum is σ = 1078896. Its totient is φ = 479844.

The previous prime is 720007. The next prime is 720019. The reversal of 720009 is 900027.

It is not a de Polignac number, because 720009 - 2¹ = 720007 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 719973 and 720000.

It is not an unprimeable number, because it can be changed into a prime (720007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1239 + ... + 1724.

It is an arithmetic number, because the mean of its divisors is an integer number (89908).

2⁷²⁰⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

720009 is a deficient number, since it is larger than the sum of its proper divisors (358887).

720009 is an equidigital number, since it uses as much as digits as its factorization.

720009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2978 (or 2966 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 18.

The square root of 720009 is about 848.5334407081. The cubic root of 720009 is about 89.6284683800.

Adding to 720009 its sum of digits (18), we get a palindrome (720027).

The spelling of 720009 in words is "seven hundred twenty thousand, nine".