12521221 has 8 divisors (see below), whose sum is σ = 12701304. Its totient is φ = 12342720.

The previous prime is 12521219. The next prime is 12521233. The reversal of 12521221 is 12212521.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2217121 + 10304100 = 1489^2 + 3210^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12521221 - 2¹ = 12521219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12521195 and 12521204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12521291) 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 in 7 ways as a sum of consecutive naturals, for example, 26931 + ... + 27391.

It is an arithmetic number, because the mean of its divisors is an integer number (1587663).

Almost surely, 2^12521221 is an apocalyptic number.

It is an amenable number.

12521221 is a deficient number, since it is larger than the sum of its proper divisors (180083).

12521221 is a wasteful number, since it uses less digits than its factorization.

12521221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 791.

The product of its digits is 80, while the sum is 16.

The square root of 12521221 is about 3538.5337358855. The cubic root of 12521221 is about 232.2106996395.

Adding to 12521221 its reverse (12212521), we get a palindrome (24733742).

The spelling of 12521221 in words is "twelve million, five hundred twenty-one thousand, two hundred twenty-one".