720909 has 12 divisors (see below), whose sum is σ = 1190176. Its totient is φ = 411912.

The previous prime is 720901. The next prime is 720913. The reversal of 720909 is 909027.

720909 is nontrivially palindromic in base 2.

It is not a de Polignac number, because 720909 - 2³ = 720901 is a prime.

It is a Duffinian number.

720909 is a modest number, since divided by 909 gives 72 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5659 + ... + 5784.

2⁷²⁰⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

720909 is a deficient number, since it is larger than the sum of its proper divisors (469267).

720909 is a wasteful number, since it uses less digits than its factorization.

720909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11456 (or 11453 counting only the distinct ones).

The product of its (nonzero) digits is 1134, while the sum is 27.

The square root of 720909 is about 849.0636018580. The cubic root of 720909 is about 89.6657975590.

The spelling of 720909 in words is "seven hundred twenty thousand, nine hundred nine".