12013521 has 32 divisors (see below), whose sum is σ = 18385920. Its totient is φ = 6921024.

The previous prime is 12013517. The next prime is 12013531. The reversal of 12013521 is 12531021.

It is not a de Polignac number, because 12013521 - 2² = 12013517 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 12013521.

It is not an unprimeable number, because it can be changed into a prime (12013501) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52810 + ... + 53036.

It is an arithmetic number, because the mean of its divisors is an integer number (574560).

Almost surely, 2^12013521 is an apocalyptic number.

It is an amenable number.

12013521 is a deficient number, since it is larger than the sum of its proper divisors (6372399).

12013521 is a wasteful number, since it uses less digits than its factorization.

12013521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 12013521 is about 3466.0526539567. The cubic root of 12013521 is about 229.0288033537.

Adding to 12013521 its reverse (12531021), we get a palindrome (24544542).

The spelling of 12013521 in words is "twelve million, thirteen thousand, five hundred twenty-one".