12507221 has 4 divisors (see below), whose sum is σ = 12845292. Its totient is φ = 12169152.

The previous prime is 12507203. The next prime is 12507241. The reversal of 12507221 is 12270521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12270521 = 41 ⋅299281.

It can be written as a sum of positive squares in 2 ways, for example, as 4884100 + 7623121 = 2210^2 + 2761^2 .

It is not a de Polignac number, because 12507221 - 2¹⁴ = 12490837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12507193 and 12507202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12507241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168980 + ... + 169053.

It is an arithmetic number, because the mean of its divisors is an integer number (3211323).

Almost surely, 2^12507221 is an apocalyptic number.

It is an amenable number.

12507221 is a deficient number, since it is larger than the sum of its proper divisors (338071).

12507221 is an equidigital number, since it uses as much as digits as its factorization.

12507221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338070.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 12507221 is about 3536.5549621065. The cubic root of 12507221 is about 232.1241222953.

Adding to 12507221 its product of nonzero digits (280), we get a triangular number (12507501 = T₅₀₀₁).

Adding to 12507221 its reverse (12270521), we get a palindrome (24777742).

The spelling of 12507221 in words is "twelve million, five hundred seven thousand, two hundred twenty-one".