7305721 has 4 divisors (see below), whose sum is σ = 7315792. Its totient is φ = 7295652.

The previous prime is 7305707. The next prime is 7305731. The reversal of 7305721 is 1275037.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1275037 = 103 ⋅12379.

It is a cyclic number.

It is not a de Polignac number, because 7305721 - 2¹⁷ = 7174649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7305731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3855 + ... + 5428.

It is an arithmetic number, because the mean of its divisors is an integer number (1828948).

Almost surely, 2^7305721 is an apocalyptic number.

It is an amenable number.

7305721 is a deficient number, since it is larger than the sum of its proper divisors (10071).

7305721 is an equidigital number, since it uses as much as digits as its factorization.

7305721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10070.

The product of its (nonzero) digits is 1470, while the sum is 25.

The square root of 7305721 is about 2702.9097284223. The cubic root of 7305721 is about 194.0384042013.

The spelling of 7305721 in words is "seven million, three hundred five thousand, seven hundred twenty-one".