13220521 has 2 divisors, whose sum is σ = 13220522. Its totient is φ = 13220520.

The previous prime is 13220461. The next prime is 13220527. The reversal of 13220521 is 12502231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13220496 + 25 = 3636^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 13220521 - 2¹¹ = 13218473 is a prime.

It is a super-2 number, since 2×13220521² = 349564351022882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 13220495 and 13220504.

It is not a weakly prime, because it can be changed into another prime (13220527) 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 as a sum of consecutive naturals, namely, 6610260 + 6610261.

It is an arithmetic number, because the mean of its divisors is an integer number (6610261).

Almost surely, 2^13220521 is an apocalyptic number.

It is an amenable number.

13220521 is a deficient number, since it is larger than the sum of its proper divisors (1).

13220521 is an equidigital number, since it uses as much as digits as its factorization.

13220521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 13220521 is about 3636.0034378422. The cubic root of 13220521 is about 236.4555561931.

Adding to 13220521 its reverse (12502231), we get a palindrome (25722752).

The spelling of 13220521 in words is "thirteen million, two hundred twenty thousand, five hundred twenty-one".