8521 has 2 divisors, whose sum is σ = 8522. Its totient is φ = 8520.

The previous prime is 8513. The next prime is 8527. The reversal of 8521 is 1258.

It is a happy number.

8521 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7225 + 1296 = 85^2 + 36^2 .

It is a cyclic number.

It is not a de Polignac number, because 8521 - 2³ = 8513 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 8495 and 8504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4260 + 4261.

It is an arithmetic number, because the mean of its divisors is an integer number (4261).

2⁸⁵²¹ is an apocalyptic number.

It is an amenable number.

8521 is a deficient number, since it is larger than the sum of its proper divisors (1).

8521 is an equidigital number, since it uses as much as digits as its factorization.

8521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80, while the sum is 16.

The square root of 8521 is about 92.3092628072. The cubic root of 8521 is about 20.4250685028.

Adding to 8521 its reverse (1258), we get a palindrome (9779).

It can be divided in two parts, 8 and 521, that added together give a square (529 = 23²).

The spelling of 8521 in words is "eight thousand, five hundred twenty-one".