7521 has 8 divisors (see below), whose sum is σ = 10560. Its totient is φ = 4752.

The previous prime is 7517. The next prime is 7523. The reversal of 7521 is 1257.

Added to its reverse (1257) it gives a triangular number (8778 = T₁₃₂).

It is a happy number.

7521 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 7521 - 2² = 7517 is a prime.

It is a plaindrome in base 13 and base 15.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 7521.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 7521.

It is not an unprimeable number, because it can be changed into a prime (7523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15 + ... + 123.

It is an arithmetic number, because the mean of its divisors is an integer number (1320).

2⁷⁵²¹ is an apocalyptic number.

It is an amenable number.

7521 is a deficient number, since it is larger than the sum of its proper divisors (3039).

7521 is a wasteful number, since it uses less digits than its factorization.

7521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135.

The product of its digits is 70, while the sum is 15.

The square root of 7521 is about 86.7236991831. The cubic root of 7521 is about 19.5925905632.

Adding to 7521 its reverse (1257), we get a palindrome (8778).

It can be divided in two parts, 7 and 521, that added together give a triangular number (528 = T₃₂).

The spelling of 7521 in words is "seven thousand, five hundred twenty-one".