12415521 has 4 divisors (see below), whose sum is σ = 16554032. Its totient is φ = 8277012.

The previous prime is 12415511. The next prime is 12415523. The reversal of 12415521 is 12551421.

12415521 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

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.

It is a de Polignac number, because none of the positive numbers 2^k-12415521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12415523) 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, 2069251 + ... + 2069256.

It is an arithmetic number, because the mean of its divisors is an integer number (4138508).

Almost surely, 2^12415521 is an apocalyptic number.

It is an amenable number.

12415521 is a deficient number, since it is larger than the sum of its proper divisors (4138511).

12415521 is an equidigital number, since it uses as much as digits as its factorization.

12415521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4138510.

The product of its digits is 400, while the sum is 21.

The square root of 12415521 is about 3523.5665170392. The cubic root of 12415521 is about 231.5554370607. Note that the first 3 decimals are identical.

Adding to 12415521 its reverse (12551421), we get a palindrome (24966942).

The spelling of 12415521 in words is "twelve million, four hundred fifteen thousand, five hundred twenty-one".