724221 has 10 divisors (see below), whose sum is σ = 1081982. Its totient is φ = 482760.

The previous prime is 724219. The next prime is 724259. The reversal of 724221 is 122427.

It can be written as a sum of positive squares in only one way, i.e., 656100 + 68121 = 810^2 + 261^2 .

It is not a de Polignac number, because 724221 - 2¹ = 724219 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 724194 and 724203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (724211) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 4390 + ... + 4551.

2⁷²⁴²²¹ is an apocalyptic number.

It is an amenable number.

724221 is a deficient number, since it is larger than the sum of its proper divisors (357761).

724221 is an equidigital number, since it uses as much as digits as its factorization.

724221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8953 (or 8944 counting only the distinct ones).

The product of its digits is 224, while the sum is 18.

The square root of 724221 is about 851.0117508002. The cubic root of 724221 is about 89.8029020082.

Adding to 724221 its reverse (122427), we get a palindrome (846648).

The spelling of 724221 in words is "seven hundred twenty-four thousand, two hundred twenty-one", and thus it is an iban number.