720609905 has 8 divisors (see below), whose sum is σ = 864961152. Its totient is φ = 576335088.

The previous prime is 720609899. The next prime is 720609907. The reversal of 720609905 is 509906027.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 720609905 - 2¹⁴ = 720593521 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (720609907) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4232 + ... + 38198.

It is an arithmetic number, because the mean of its divisors is an integer number (108120144).

Almost surely, 2^720609905 is an apocalyptic number.

It is an amenable number.

720609905 is a deficient number, since it is larger than the sum of its proper divisors (144351247).

720609905 is a wasteful number, since it uses less digits than its factorization.

720609905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38215.

The product of its (nonzero) digits is 34020, while the sum is 38.

The square root of 720609905 is about 26844.1782329055. The cubic root of 720609905 is about 896.5339548448.

The spelling of 720609905 in words is "seven hundred twenty million, six hundred nine thousand, nine hundred five".