2521 has 2 divisors, whose sum is σ = 2522. Its totient is φ = 2520.

The previous prime is 2503. The next prime is 2531. The reversal of 2521 is 1252.

2521 = 35² + 36².

2521 is nontrivially palindromic in base 16.

It is the 21-st star number.

It is an a-pointer prime, because the next prime (2531) can be obtained adding 2521 to its sum of digits (10).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1296 + 1225 = 36^2 + 35^2 .

It is a cyclic number.

It is not a de Polignac number, because 2521 - 2⁷ = 2393 is a prime.

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

2521 is an undulating number in base 16.

It is a plaindrome in base 13.

It is a nialpdrome in base 14 and base 15.

It is a junction number, because it is equal to n+sod(n) for n = 2498 and 2507.

It is not a weakly prime, because it can be changed into another prime (2531) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1260 + 1261.

It is an arithmetic number, because the mean of its divisors is an integer number (1261).

2521 is the 36-th centered square number.

It is an amenable number.

2521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2521 is an equidigital number, since it uses as much as digits as its factorization.

2521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20, while the sum is 10.

The square root of 2521 is about 50.2095608425. The cubic root of 2521 is about 13.6099840182.

Adding to 2521 its reverse (1252), we get a palindrome (3773).

It can be divided in two parts, 252 and 1, that added together give a triangular number (253 = T₂₂).

The spelling of 2521 in words is "two thousand, five hundred twenty-one".