12017521 has 4 divisors (see below), whose sum is σ = 12724452. Its totient is φ = 11310592.

The previous prime is 12017497. The next prime is 12017539. The reversal of 12017521 is 12571021.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12571021 = 139 ⋅90439.

It can be written as a sum of positive squares in 2 ways, for example, as 9734400 + 2283121 = 3120^2 + 1511^2 .

It is a cyclic number.

It is not a de Polignac number, because 12017521 - 2⁷ = 12017393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12017561) 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, 353440 + ... + 353473.

It is an arithmetic number, because the mean of its divisors is an integer number (3181113).

Almost surely, 2^12017521 is an apocalyptic number.

It is an amenable number.

12017521 is a deficient number, since it is larger than the sum of its proper divisors (706931).

12017521 is an equidigital number, since it uses as much as digits as its factorization.

12017521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 706930.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 12017521 is about 3466.6296312124. The cubic root of 12017521 is about 229.0542195370.

Adding to 12017521 its reverse (12571021), we get a palindrome (24588542).

The spelling of 12017521 in words is "twelve million, seventeen thousand, five hundred twenty-one".