720646 has 4 divisors (see below), whose sum is σ = 1080972. Its totient is φ = 360322.

The previous prime is 720619. The next prime is 720653. The reversal of 720646 is 646027.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 720646.

It is a congruent number.

It is an unprimeable number.

720646 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 180160 + ... + 180163.

It is an arithmetic number, because the mean of its divisors is an integer number (270243).

2⁷²⁰⁶⁴⁶ is an apocalyptic number.

720646 is a deficient number, since it is larger than the sum of its proper divisors (360326).

720646 is a wasteful number, since it uses less digits than its factorization.

720646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360325.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 720646 is about 848.9087112287. The cubic root of 720646 is about 89.6548923578.

The spelling of 720646 in words is "seven hundred twenty thousand, six hundred forty-six".