13521421 has 2 divisors, whose sum is σ = 13521422. Its totient is φ = 13521420.

The previous prime is 13521419. The next prime is 13521437. The reversal of 13521421 is 12412531.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8185321 + 5336100 = 2861^2 + 2310^2 .

It is a cyclic number.

It is not a de Polignac number, because 13521421 - 2¹ = 13521419 is a prime.

Together with 13521419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13521461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6760710 + 6760711.

It is an arithmetic number, because the mean of its divisors is an integer number (6760711).

Almost surely, 2^13521421 is an apocalyptic number.

It is an amenable number.

13521421 is a deficient number, since it is larger than the sum of its proper divisors (1).

13521421 is an equidigital number, since it uses as much as digits as its factorization.

13521421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 240, while the sum is 19.

The square root of 13521421 is about 3677.1484876192. The cubic root of 13521421 is about 238.2360309387.

Adding to 13521421 its reverse (12412531), we get a palindrome (25933952).

The spelling of 13521421 in words is "thirteen million, five hundred twenty-one thousand, four hundred twenty-one".