720905 has 8 divisors (see below), whose sum is σ = 893184. Its totient is φ = 558000.

The previous prime is 720901. The next prime is 720913. The reversal of 720905 is 509027.

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

It is not a de Polignac number, because 720905 - 2² = 720901 is a prime.

It is a Duffinian number.

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

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2171 + ... + 2480.

It is an arithmetic number, because the mean of its divisors is an integer number (111648).

2⁷²⁰⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

720905 is a deficient number, since it is larger than the sum of its proper divisors (172279).

720905 is a wasteful number, since it uses less digits than its factorization.

720905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4687.

The product of its (nonzero) digits is 630, while the sum is 23.

The square root of 720905 is about 849.0612463185. The cubic root of 720905 is about 89.6656317203.

The spelling of 720905 in words is "seven hundred twenty thousand, nine hundred five".