13521581 has 2 divisors, whose sum is σ = 13521582. Its totient is φ = 13521580.

The previous prime is 13521551. The next prime is 13521593. The reversal of 13521581 is 18512531.

It is a happy number.

13521581 is nontrivially palindromic in base 11.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11792356 + 1729225 = 3434^2 + 1315^2 .

It is a cyclic number.

It is not a de Polignac number, because 13521581 - 2⁶ = 13521517 is a prime.

It is a super-2 number, since 2×13521581² = 365666305479122, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 13521581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13521551) 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, 6760790 + 6760791.

It is an arithmetic number, because the mean of its divisors is an integer number (6760791).

Almost surely, 2^13521581 is an apocalyptic number.

It is an amenable number.

13521581 is a deficient number, since it is larger than the sum of its proper divisors (1).

13521581 is an equidigital number, since it uses as much as digits as its factorization.

13521581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1200, while the sum is 26.

The square root of 13521581 is about 3677.1702435433. The cubic root of 13521581 is about 238.2369706234.

The spelling of 13521581 in words is "thirteen million, five hundred twenty-one thousand, five hundred eighty-one".