720621 has 24 divisors (see below), whose sum is σ = 1179360. Its totient is φ = 420000.

The previous prime is 720619. The next prime is 720653. The reversal of 720621 is 126027.

It is a happy number.

It is not a de Polignac number, because 720621 - 2¹ = 720619 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 720594 and 720603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720611) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2746 + ... + 2996.

It is an arithmetic number, because the mean of its divisors is an integer number (49140).

2⁷²⁰⁶²¹ is an apocalyptic number.

It is an amenable number.

720621 is a deficient number, since it is larger than the sum of its proper divisors (458739).

720621 is a wasteful number, since it uses less digits than its factorization.

720621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297 (or 294 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 720621 is about 848.8939863140. The cubic root of 720621 is about 89.6538556037.

Adding to 720621 its reverse (126027), we get a palindrome (846648).

It can be divided in two parts, 7206 and 21, that added together give a palindrome (7227).

The spelling of 720621 in words is "seven hundred twenty thousand, six hundred twenty-one".