12551221 has 4 divisors (see below), whose sum is σ = 12571744. Its totient is φ = 12530700.

The previous prime is 12551213. The next prime is 12551239. The reversal of 12551221 is 12215521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12215521 = 109 ⋅112069.

It is a cyclic number.

It is not a de Polignac number, because 12551221 - 2³ = 12551213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12551291) 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 3 ways as a sum of consecutive naturals, for example, 9315 + ... + 10576.

It is an arithmetic number, because the mean of its divisors is an integer number (3142936).

Almost surely, 2^12551221 is an apocalyptic number.

It is an amenable number.

12551221 is a deficient number, since it is larger than the sum of its proper divisors (20523).

12551221 is an equidigital number, since it uses as much as digits as its factorization.

12551221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20522.

The product of its digits is 200, while the sum is 19.

The square root of 12551221 is about 3542.7702437499. The cubic root of 12551221 is about 232.3960054434.

Adding to 12551221 its reverse (12215521), we get a palindrome (24766742).

The spelling of 12551221 in words is "twelve million, five hundred fifty-one thousand, two hundred twenty-one".