12213521 has 2 divisors, whose sum is σ = 12213522. Its totient is φ = 12213520.

The previous prime is 12213517. The next prime is 12213527. The reversal of 12213521 is 12531221.

It is a happy number.

12213521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10923025 + 1290496 = 3305^2 + 1136^2 .

It is an emirp because it is prime and its reverse (12531221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12213521 - 2² = 12213517 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12213521.

It is not a weakly prime, because it can be changed into another prime (12213527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6106760 + 6106761.

It is an arithmetic number, because the mean of its divisors is an integer number (6106761).

Almost surely, 2^12213521 is an apocalyptic number.

It is an amenable number.

12213521 is a deficient number, since it is larger than the sum of its proper divisors (1).

12213521 is an equidigital number, since it uses as much as digits as its factorization.

12213521 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 12213521 is about 3494.7848288557. The cubic root of 12213521 is about 230.2927651796.

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

The spelling of 12213521 in words is "twelve million, two hundred thirteen thousand, five hundred twenty-one".