720641 has 4 divisors (see below), whose sum is σ = 734292. Its totient is φ = 706992.

The previous prime is 720619. The next prime is 720653. The reversal of 720641 is 146027.

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

It can be written as a sum of positive squares in 2 ways, for example, as 270400 + 450241 = 520^2 + 671^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720611) 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 3 ways as a sum of consecutive naturals, for example, 6746 + ... + 6851.

It is an arithmetic number, because the mean of its divisors is an integer number (183573).

2⁷²⁰⁶⁴¹ is an apocalyptic number.

It is an amenable number.

720641 is a deficient number, since it is larger than the sum of its proper divisors (13651).

720641 is a wasteful number, since it uses less digits than its factorization.

720641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13650.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 720641 is about 848.9057662662. The cubic root of 720641 is about 89.6546850089.

Adding to 720641 its reverse (146027), we get a palindrome (866668).

The spelling of 720641 in words is "seven hundred twenty thousand, six hundred forty-one".