7230721 has 3 divisors (see below), whose sum is σ = 7233411. Its totient is φ = 7228032.

The previous prime is 7230709. The next prime is 7230731. The reversal of 7230721 is 1270327.

The square root of 7230721 is 2689.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 261121 + 6969600 = 511^2 + 2640^2 .

It is a de Polignac number, because none of the positive numbers 2^k-7230721 is a prime.

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

7230721 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 7230692 and 7230701.

It is not an unprimeable number, because it can be changed into a prime (7230701) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1345 + ... + 4033.

It is an arithmetic number, because the mean of its divisors is an integer number (2411137).

Almost surely, 2^7230721 is an apocalyptic number.

7230721 is the 2689-th square number.

7230721 is the 1345-th centered octagonal number.

It is an amenable number.

7230721 is a deficient number, since it is larger than the sum of its proper divisors (2690).

7230721 is an frugal number, since it uses more digits than its factorization.

7230721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5378 (or 2689 counting only the distinct ones).

The product of its (nonzero) digits is 588, while the sum is 22.

The cubic root of 7230721 is about 193.3721242681.

The spelling of 7230721 in words is "seven million, two hundred thirty thousand, seven hundred twenty-one".