7518521 has 4 divisors (see below), whose sum is σ = 7527972. Its totient is φ = 7509072.

The previous prime is 7518517. The next prime is 7518529. The reversal of 7518521 is 1258157.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1258157 = 101 ⋅12457.

It can be written as a sum of positive squares in 2 ways, for example, as 4494400 + 3024121 = 2120^2 + 1739^2 .

It is a cyclic number.

It is not a de Polignac number, because 7518521 - 2² = 7518517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7518529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3410 + ... + 5163.

It is an arithmetic number, because the mean of its divisors is an integer number (1881993).

Almost surely, 2^7518521 is an apocalyptic number.

It is an amenable number.

7518521 is a deficient number, since it is larger than the sum of its proper divisors (9451).

7518521 is an equidigital number, since it uses as much as digits as its factorization.

7518521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9450.

The product of its digits is 2800, while the sum is 29.

The square root of 7518521 is about 2741.9921589968. The cubic root of 7518521 is about 195.9043768597.

The spelling of 7518521 in words is "seven million, five hundred eighteen thousand, five hundred twenty-one".