12221521 has 12 divisors (see below), whose sum is σ = 13985692. Its totient is φ = 10614528.

The previous prime is 12221519. The next prime is 12221527. The reversal of 12221521 is 12512221.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 2387025 + 9834496 = 1545^2 + 3136^2 .

It is not a de Polignac number, because 12221521 - 2¹ = 12221519 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12221495 and 12221504.

It is not an unprimeable number, because it can be changed into a prime (12221527) 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 11 ways as a sum of consecutive naturals, for example, 2131 + ... + 5383.

Almost surely, 2^12221521 is an apocalyptic number.

It is an amenable number.

12221521 is a deficient number, since it is larger than the sum of its proper divisors (1764171).

12221521 is a wasteful number, since it uses less digits than its factorization.

12221521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3300 (or 3283 counting only the distinct ones).

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

The square root of 12221521 is about 3495.9292040887. The cubic root of 12221521 is about 230.3430356958.

Adding to 12221521 its reverse (12512221), we get a palindrome (24733742).

The spelling of 12221521 in words is "twelve million, two hundred twenty-one thousand, five hundred twenty-one".