7520721 has 16 divisors (see below), whose sum is σ = 10940160. Its totient is φ = 4567680.

The previous prime is 7520719. The next prime is 7520729. The reversal of 7520721 is 1270257.

It is not a de Polignac number, because 7520721 - 2¹ = 7520719 is a prime.

It is a super-2 number, since 2×7520721² = 113122488719682, which contains 22 as substring.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 7520691 and 7520700.

It is not an unprimeable number, because it can be changed into a prime (7520729) 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 15 ways as a sum of consecutive naturals, for example, 1861 + ... + 4301.

It is an arithmetic number, because the mean of its divisors is an integer number (683760).

Almost surely, 2^7520721 is an apocalyptic number.

It is an amenable number.

7520721 is a deficient number, since it is larger than the sum of its proper divisors (3419439).

7520721 is a wasteful number, since it uses less digits than its factorization.

7520721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2536.

The product of its (nonzero) digits is 980, while the sum is 24.

The square root of 7520721 is about 2742.3932978331. The cubic root of 7520721 is about 195.9234829046.

Adding to 7520721 its reverse (1270257), we get a palindrome (8790978).

The spelling of 7520721 in words is "seven million, five hundred twenty thousand, seven hundred twenty-one".