720321 has 8 divisors (see below), whose sum is σ = 1097664. Its totient is φ = 411600.

The previous prime is 720319. The next prime is 720359. The reversal of 720321 is 123027.

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

It is not a de Polignac number, because 720321 - 2¹ = 720319 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 720321.

It is not an unprimeable number, because it can be changed into a prime (720301) 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, 17130 + ... + 17171.

It is an arithmetic number, because the mean of its divisors is an integer number (137208).

2⁷²⁰³²¹ is an apocalyptic number.

It is an amenable number.

720321 is a deficient number, since it is larger than the sum of its proper divisors (377343).

720321 is a wasteful number, since it uses less digits than its factorization.

720321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34311.

The product of its (nonzero) digits is 84, while the sum is 15.

The square root of 720321 is about 848.7172674101. The cubic root of 720321 is about 89.6414126829.

Adding to 720321 its reverse (123027), we get a palindrome (843348).

The spelling of 720321 in words is "seven hundred twenty thousand, three hundred twenty-one", and thus it is an iban number.