12531221 has 2 divisors, whose sum is σ = 12531222. Its totient is φ = 12531220.

The previous prime is 12531209. The next prime is 12531247. The reversal of 12531221 is 12213521.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6838225 + 5692996 = 2615^2 + 2386^2 .

It is an emirp because it is prime and its reverse (12213521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12531221 - 2²² = 8336917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12531221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12531121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6265610 + 6265611.

It is an arithmetic number, because the mean of its divisors is an integer number (6265611).

Almost surely, 2^12531221 is an apocalyptic number.

It is an amenable number.

12531221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12531221 is an equidigital number, since it uses as much as digits as its factorization.

12531221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120, while the sum is 17.

The square root of 12531221 is about 3539.9464685218. The cubic root of 12531221 is about 232.2725010962.

Adding to 12531221 its reverse (12213521), we get a palindrome (24744742).

The spelling of 12531221 in words is "twelve million, five hundred thirty-one thousand, two hundred twenty-one".