7229721 has 4 divisors (see below), whose sum is σ = 9639632. Its totient is φ = 4819812.

The previous prime is 7229713. The next prime is 7229741. The reversal of 7229721 is 1279227.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 7229721 - 2³ = 7229713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7229711) 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, 1204951 + ... + 1204956.

It is an arithmetic number, because the mean of its divisors is an integer number (2409908).

Almost surely, 2^7229721 is an apocalyptic number.

It is an amenable number.

7229721 is a deficient number, since it is larger than the sum of its proper divisors (2409911).

7229721 is a wasteful number, since it uses less digits than its factorization.

7229721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2409910.

The product of its digits is 3528, while the sum is 30.

The square root of 7229721 is about 2688.8140508410. The cubic root of 7229721 is about 193.3632094799.

The spelling of 7229721 in words is "seven million, two hundred twenty-nine thousand, seven hundred twenty-one".